Is there any reason not to use a nut & bolt instead?
Have many mechanical reasons, one of them is the diameter they can use and the screw head size, i can see many others but this one is surely the main. Such mechanical fixture always be a problem in the past, the technologies have evolve but MMC don't and for cost reasons they keep using on shelf solution. Improve it always at the expense of the owner, and we can't rely on so many supplier for develop and invest on such things because of the nature of the community.
Just days ago reading a post in facebook a guy said: sorry i am a Yorkshire men so i will save 20£ and look elsewhere for a cheaper solution, reading this it's easy to understand why we don't have supplier invest on our cars, they almost all do: made to order on simple things with only request raw material, even the badge have to be sold or pre-order before manufacture it.
I can list here several interesting project in Morgan field i have see never see the light because they see the market will not be there, let said for example the double wishbone for replace the King Pin
