As ever it seems the MMC might be a tad behind the times, which is fine by me. As best I can remember it took the then MMC quite a while to catch up with Harley as to the possible value in the name or even the bonnet badge, and as best I can remember the outline of a trad, when they got round to realising the value in registering such things as copywrite...?
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.Ramble alert on parts supply over a few decades and not a lot Morgan related, but hopefully enough...
I guess as might be expected of me that I might just suggest dipping into have a look at the way Porsche have created their own way of catering to their classics...?
I am well aware that being nearer 80 than 70 years old, my thinking on prices can be a bit off at times and by quite some margin, even for everyday items, though 50 years ago I thought Porsche prices seemed to me to be way over the top... As an example from back then, Porsche being an air cooled engine, it had both an inner and an outer valve spring on each cylinder head valve, the cost back then for replacement per valve was £25, whereas one could buy a whole set of valve springs (8) for an MGB for £14...
To my mind, in terms of Trads overall there is not a lot of sophisticated engineering in terms of mechanicals that is different from the mass produced vehicles that the MMC used as donors for the majority of their engines gearboxes and braking systems, such as might be found on any Porsche of a similar era.... As to whether the cost difference for parts might be justified or not, is for you to judge, Back then I just had to suck it up, much as I do today, though for very different reasons. Back then the quality of Porsche engineering compared to all others of my cars that I had worked on over the years was superior in numerous ways, thus in some way the cost difference seemed justified to some degree.
As for my local Porsche dealership, I required to replace a cylinder barrel on my Porsche, none could be found in the UK or Germany in the 70`s for my 912, apparently the majority of 912`s were to be found in the US, some 80% or so of those seemingly to be found in California... Thus Porsche Germany sourced the correct barrel in the US and had it sent to my local Porsche dealership, at no extra cost to me..
There are of course Porsche parts suppliers who have been around for years, and know well where Porsche source many of their parts and these suppliers buy direct from the original manufacturers of the parts to cut the cost of parts both to the trade and enthusiasts.... However on occasion apparently it has been reported that in some cases buying from Porsche can be less costly.
Porsche themselves were obviously well aware of the growth in aftermarket prices even back in the 80`s and as best I can remember Porsche had an advertising campaign to warn of quality issues relative to fake parts carrying the Porsche name either on the packaging or even cast into the fabric of the part.... I seem to remember the Porsche adds carried photographs of X-ray images of "fake" break discs and wheels that had obvious flaws within their construction.... Causing me to remember some documentary TV prog, where a native craftsman sitting in the street outside a "workshop" finishing off the construction of a Kalashnikov automatic rifle while using his feet as a vice... and which caused me to apply the "term mud hut manufacture" relative to the likely quality difference between fake and real Original Equipment (OE) parts.
Time has moved on, and in circa the early 80`s I remember ordering parts for my then long term restoration project MGB from a recognised aftermarket supplier of MG parts. One of the early tasks I set to was rebuilding the B`s front suspension and fitting new rubber bushes on important pivoting points, the body was left jacked up for month after month while I welded in all the normally required replacement panels. When all the welding was finally finished, and while I was in the process of jacking it up to remove all the jack stands, I noted that the rubbers I had renewed some months previously were now showing multiple cracks....Hmm..!
OK so it seems even long established and recognised suppliers of common parts for Brit sports cars may well have been looking for cost cutting in terms of their supply chain, much like every other business, even down to those supplying aircraft parts... Hmm..? I doubt there is any surprise found in such practices today, perhaps 40 or more years on...?
Without any first hand knowledge, I suspect it is in no way unusual in the rush to cut costs that many UK "household" names in many industries sought to cut costs and perhaps even off-shored the production of their parts... In some cases perhaps the quality even improved, but maybe not always...? I have read where Porsche had supply issues with parts manufactured in Ukraine, whether true or not, I have no idea.
As for costs, I have a pal who is a died in the wool Ford enthusiast, and tells me just how much fellow enthusiasts are prepared for very rare O.E. body panels for the likes of a 70`s Capri, and identified as such by almost illegible and original Ford labels still stuck to the panels...As with all markets I guess it is down to supply and demand but enough to say I was really shocked having a reasonable idea of the cost of these old panels when they were new...!!!
So I back to Morgan spares..... I think way back in time it seems possible that the MMC may have sourced parts to construct new Morgans by raiding the parts bin of larger manufacturers end of line models..? I do not know for sure but think it was suggested to me some time back that the rear brake shoes and perhaps other brake components on my mid 80`s +8 may have been originally found on a 60`s Ford Zodiac, or similar.... ?
I guess if today I wished to find a set of brake shoes originally as fitted to my +8, going to a Ford dealership might seem less than wise... (-: the MMC.. or perhaps a Morgan specialist who may have had them sitting on a shelf gathering dust for quite some time.... as for the likely value attributed to these shoes.. relative to the cost of storing them in serviceable condition over time...against their value to mein order to keep my Morgan roadworthy... Hmm..?
For sure I have been around long enough to have bought brake shoe linings directly from Mintex, and riveted them on to the shoes myself, I have also in many years past taken worn Porsche handbrake shoes into the same company who would strip the worn linings off and bond on replacements at a FRACTION of the cost I would have paid, not only from Porsche, but from then recognised and respected aftermarket Porsche parts suppliers..
Bottom line is business is business is it not...? That being the case, I guess much depends upon how much TIME and effort one may wish to put into investigating where the best quality/priced parts may be found, which can be no easy task, thus paying a premium for either ones lack of knowledge or convenience of supply may be just thought to be worth the cost.... or not...?
So there you have it, my cynical thinking on the mix of quality and price on even the most basic of parts...But as ever I am just thinking in type, no expertise claimed whatsoever, treat it as you would any fake news..(-:
OK I almost forgot to post the Porsche classic parts link, for the few Morganeers with interest in things Porsche related.... and I know there will be a few... (-: I hope the link works but if not, it can easily found on the www.
https://www.porsche.com/uk/accessoriesandservice/classic/
It is a question of market size. There are likely 20,000+ trads on the road. Compare that to the Aero market. Current models, I imagine, will be supplied separately, as they are now, by current production. I can tell you that you CAN probably get Aero I wings soon, something that has not been possible for over 20 years. 
I can argue with that. I give out or search for parts a dozen times a week, most find their way into forum thread. In my searches, I try to insist they are to be the RIGHT parts and reasonably priced. I constantly see other parts, from other cars, substituted, often when the original better part is available