Here's my take.Tits don't book bands, club managers book bands.
Club managers book bands in order to get people to come to the club, pay the cover charge, and buy food/drinks.
Thus, club managers will book whatever band they think will attract an audience.
If they think tits will attract an audience at their club, they will book tits. If they think ugly people doing fabulous music will attract an audience at their club, they will book ugly people doing fabulous music. And so forth.
It's really a measure of what the club managers think their potential patrons want to see/hear.
How to change it? Easy. Go to lots of shows with good music. Refuse to go to shows where the music is lousy but the singer is shapely. Club managers, being business people, will book what sells.
Swat my 'hind with a melon rind,
But that's my penguin state-of-mind
-Opus the Penguin, Bloom County