(Note: I realize that no definitive answer can be given to this question, and sheer speculation is required to give any answer at all. But I’m hoping to get informed speculation from people who’ve made some study of the musical environment as it stood in the 1960’s.)
One of the classic instances of a Really Bad Decision is that made by Decca Records, who in 1962 rejected an audition tape by the Beatles, on the grounds that ‘guitar bands are on the way out’.
Obviously, Decca was (rather spectacularly) wrong on this particular judgement. On the other hand, they weren’t exactly some fly-by-night company at the time, and I assume they must have had some good reason to make that decision. So my question is: If Decca actually did believe guitar bands had run their course, what did they think was on the way in? If we lived in some alternate universe where Decca had turned out to be right, what sort of music might we have expected in the next decade or two?