Just some scattered remarks:
My musical life has been shaped mostly by American guitar playing. Robert Johnson, Blind Blake, Leadbelly, Tampa Red, Fahey, Cooder, Kottke, Captain Beefheart's bands, etc. - generally, what's now called Americana. I had the fortune of seeing Jimi Hendrix live, and how he virtually reinvented the Fender Stratocaster, which was thought of as a twang/surf guitar before he burst on the scene. His liberating approach opened the way for the likes of EVH and technique-oriented "shredding" in general, including still current virtuoso "metal" styles. The one guy I wish I'd been aware of when it mattered was the fantastic and under-recorded Arthur Rhames, who died so young.
But contrary to monetary thinking, nothing can grow forever. It's obvious that the heady guitar era in popular music has been in decline for quite some time. With developing electronics, the world is going abstract. Digital technology "democratized" recording, so that anyone can now piece together something surprising and personal, if not actually musical. Postmodernism decrees that there be no real truths and no valid authorities on anything, so you don't need to woodshed or acquire any skills to be taken seriously. Art is as art does these days.
As for acoustics outselling electrics, I heard the same from my local guy, who has run his import business since 1980. He thought Taylor, a notable long-time builder, had really hit gold lately - because of Taylor Swift.
1970-ish, the British guitar educator Bert Weedon opined in the
Melody Maker: "The guitar is the instrument of the '70s and '80s." I recall reading that and thinking, well, old man, it might go much farther than you think. But on reflection, I guess he was right in the main.
Accordion shop? Wow. Don't think I have ever heard of one in North America. ...
Chicago, for instance, used to have several accordion importers catering to the Italian immigrant community. In the mid-'60s, when The Beatles had hit the planet, most diverged into electric guitars - produced by erstwhile accordion manufacturers in Italy, who continued using their traditional pearloid materials for finishes.