Everyone liked Top 40? There were many FM stations that played Album Rock and became quite successful. If a AAA format can get good ratings and reach affluent demos, a competent salesman should be able to find clients. Sometimes the problem is the sales staff, not the programming. That may be a hard pill to swallow, but it's true...
But Top 40 was, through the end of the 80's, the mass appeal format. While a smaller group went to AOR, the larger group was with Top 40. It was not the core format for everyone, but seeing the format cuming over 50% of all non-ethnic people in individual markets was not unusual.
In many markets, going back to the 80's, oldies (not renamed to Classic Hits) and Country shared lots of listeners. AOR shared with just about nobody.
Anecdotally, one of my daughters is an attorney in her 40's. She still checks her local CHR station regularly to hear what new music is out. She is not a P1, or even P2... but she listens. That is the core to understanding the format.
AAA only gets decent numbers in a few markets on commercial stations... Portland and Denver being the standouts. But both are nearly 50-year heritage stations that have kept up with the music, lifestyle and market.
In most markets it under-performs and has a hard to sell image. Take KSCA in LA some 23 years ago... years at the under-2 share performance and agencies thought the audience was mostly tokers and worse. And that is despite being owned by market legend Gene Autrey and managed by a local iconic manager.
No matter how good the sellers, if clients don't like the format they will not buy. The same thing happened to Stern in many markets: bail bondsmen, pawn shops and cheap car insurance for the un-insurable were the core accounts.
Sellers can't create a need that does not exist and get renewals. If clients in a market are predisposed or prejudiced against a format, they will not buy it.
To disprove your theory, ask anyone who tried to sell Spanish language radio in the 70's if they were able to win over biased buyers. Buy me a beer or two and I can go on for hours with anecdotes about that experience... things like "your listeners don't buy my cars... they steal them".