That used to be not such a bad idea when FM didn't really enter the picture because there were far fewer competitive signals. In Portland OR, for about half of the 1960s, all viable signals were some kind of MOR(KOIN was actually CBS block programming, left over from pre-television.)except KWJJ which switched from MOR to Country in 1965 and KISN, the local Top 40 outlet. By the way, it occurred to me that some people may have grown up entirely on just one Top 40 station and since in those days, they really played all popular genres that it might be possible that not being able to change stations, when an unliked song played,(We couldn't even tune out the commerials!)might have a wider appreciation for music. This could be at least part of the reason that some on this board steadfastly cling to the idea of large playlists.
That's perhaps the best point made in this entire multi-year-long set of threads about playlist length and variety on classic hits / oldies stations.
My early adolescent experience with Top 40 was in a former Top 10 market in the era when FM had no impact or audience. There were 8 stations, including one daytimer. At any given moment, 3 were MOR variants, 3 were Top 40 variants and two, including the daytimer, were r&b stations.
The Top 40's played everything from Dean Martin, Dominico Modugno and Dave "Baby" Cortez to Frankie Avalon, Little Richard and Buddy Holly. I despised the former and loved (most of) the latter. So, given several Top 40's to chose from, I would tune out "Mac the Knife" and look for something more "hip" on one of the other stations. But when I couldn't immediately switch the dial, I got exposed to "Happy Organ" and "Nel Blu Dipinto Di Blu" and did, as you say, develop a liking for some and a tolerance for others.
Today, that market has about 20 different formats or variants, as well as all market's exposure to satellite and new media music sources. One can indulge a niche preference much more easily and avoid exposure to less preferred genres.
Again, great point.
I do, based on your observation, wonder when listeners began to be much more focused on one kind of music and less exposed to others. I would guess that it started with Motown, and enhanced by the British Invasion which were points when the MOR and "throwback" genres tended to be eliminated from Top 40. Of course, the beginning of real fragmentation was the time of the FCC's mandate to end most AM/FM simulcasts in 1967. But anyone growing up in the late 50's and early to mid 60's did get the cross-genre exposure you mention.
Good stuff to think about!