> One possibility is that touring musicians lose touch with ordinary life, and therefore no longer create anything that people can relate to.

Reminds me of an article I read about R.E.M. around the turn of the millennium. The journalist notes that the band members (now all multi-millionaires) now spent their time moving from one posh luxury hotel or perfectly air-conditioned space to another around the world, living in an international cosmopolitan bubble even when not touring. This seemed the very antithesis of the struggle and feeling of local community from which several great rock subgenres had emerged, and it was no surprise that R.E.M.'s work had become bland.

Was listening to Rick Rubin interview Andre Benjamin on Broken Record, and they briefly touched on this and agreed that constant touring creates a bubble that is terrible for writers.

In another part of the interview, Andre Benjamin said he loved going to the laundromat, and his biggest musical aspiration (at the time of the interview) was to play the bass clarinet well enough to be able to play along with anything/anyone at the park or beach (condensing/paraphrasing).

I think it's a combination of things, the career of a pop musician appears to be terrible for their art - probably bad for most of them as people, too.

There is an old observation that as comedians get older and more famous, they all start to tell jokes almost exclusively about airlines and travel.