I know many builders have been lost as a result of old age and there are less and less followers to fill their shoes, that can't be the only reason "GO for it".

a) I know lots and lots of builders that went "underground" and from there there is no coming back
b) Less people are going into building RC, and now they have a choice: ARFs. You need a pool of "new" builders to compensate those that die or cannot build anymore.
c) Many are actually out at the field more often thanks to ARFS

At least this is my observation. For many years if you flew RC you were a builder, period. Not anymore, now there is a choice, and many are choosing to fly over working in the shop. And that, in a nutshell, is the truth. Can you handle the truth?:-)

Gerry
PS: I can only speak for myself, and talk about my personal experience. Other people's experiences might vary:-)