Read other letters about this article
Half the people own iPods or (like me) old cd Walkmans. Taste is so different that there is no way a gym can cater to everyone. My guess is that they play the kind of music they play because the hardcore regulars like it. The big guys and buff gals who do tons of lifting and talk regularly with the staff. I doubt the opinion of anyone else matters to them.
Personally, I listen to opera, and I listen to a lot of cast albums. I particularly like the latter because more recent shows tend to have 7-10 minute opening numbers which are very up tempo, and that pushes me at the start. Usually a couple of "up" numbers of shorter duration follow, after which comes a ballad. That fits my own energy cycle perfectly. But what are the chances that anyone else there at a given time has the same taste? Or the same pattern?
It makes the most sense for people to bring their own music to suit their own needs.