nah they make more.... its only when the demand drops off on certain bits that they kill them off.
take a infiniti Q45 - try to buy bits for one of those. not a popular car and bits VERY hard to find new.
this thing I can pull up on my lookup list and get parts prices and the like quite easily.
to put it another way , if everyone keeps restoring R32 GTRs then the GTST or GTS4 will still live as well.
some parts are getting expensive though. the alloy GTR bonnet is a touch under $2k new..