If there were more demand from an expanded pool of playes for expensive instruments their price would come down.

That's already happened, years ago, giving rise to the production of cheap mass produced instruments. For the most part, they are nothing like as good. Making good instruments demands a very high level of skill and a certain amount of time, neither of which can be compromised without reducing the quality of the instrument. Then there are the materials, likewise.

Then listen and learn then adapt and write more....easy

Sort of like songwriters do? Those people you want to exclude from folk music?