A friend of mine bought a Mercedes for over £30k when I bought my Roadster in 08. He recently let it go with less mileage than my Roadster for about £10k. Not a reason to buy a Morgan but an example of why I don't get excited about moderns.
The depreciation was a factor when buying a Porsche, not the major one but a factor nonetheless. I was very tempted by a Cayman, beautiful to look at and a stunning drive BUT I like older cars in general and the air cooled 911 ticked all the boxes without (hopefully) no depreciation. As for my 69 4/4 Morgan, depreciation wasn't really a factor when I bought it, I just loved the car even though I knew in a few years it would require a rebuild (now in slow progress). I doubt it will be worth a fortune once rebuilt and I will have put in more money than it will be worth but it is a great ownership experience driving and rebuilding.