There was a column in Octane magazine this month suggesting a 'listed vehicle' scheme should be created, so certain cars remain as they were, rather than being cut about, or re-bodied, as otherwise all pre-war Bentleys will be open top and dark green eventually.
Thankfully I doubt all Golf1s will wind up as 20VTs although you might struggle to find any on standard height springs. 
That's not a bad idea for properly rare cars. Owning one wouldn't be so bad as being listed would proberbly increase their value.
OK my mk1 comment wasn't exactly serious but my point still stands to a degree. Once people stop transplanting because they want to, they will do it because they feel they have to eventually. There will always be purists though I suppose. I'm kind of 50/50. Certainly don't want to be modernising mine too much mechanically with parts that weren't available when built.
I say that now though

You're right about suspension, even concourse cars I see aren't even standard these days.