VW and Minis benefit from the fact that they made them for a while and didn't change much of anything, and they had virtually 1 model.

There are reproduction parts for Z's and roadsters, even 510's, the 210(120y)/1200 don't seem to catch the collector's eye. Look on ebay, pages of Z parts, pages of 510 parts, search for 210's and there's a page or 2 of crap if you're lucky.

the economy car image of the 210 hasn't helped it, it's made it into the disposable car to drive till it falls apart and is scrapped. By the time 210's are appreciated there will be very few left.