It´s also harder to find public domain sheets of lesser known composers. If the choice stands between a fully printed Schubert piece three clicks away or 30 minutes research on google and 2 weeks mail delivery, what would the majority chose?
It only seems reasonable to point out that there is a vast amount of readily available sheet public domain music by lesser-known composers on IMSLP, and therefore I don't feel this works as a justification for not playing lesser-known pieces.
So, at the risk of sounding like a proselytizing bore, why do people not play it?
1) it's crap?
2) they don't know about IMSLP and similar sites?
3) they do know of IMSLP etc, but are too lazy to look?
4) there's no point in learning it, because no-one wants to hear it?
5) they have no intellectual curiosity and don't want to look outwith the accepted repertoire
(from my experience: 1 = sometimes true, 4 = definitely false). I'm genuinely interested in what the reason is btw.