From what I understand, a lot of the commercial beeks regularly use medications. In addition to Thymol, there is Check Mite and Mite Away. There are probably a couple that I'm missing. I know some guys don't like to use chemicals, and prefer to use powdered sugar.
I am no scientist, but I do think there is a correlation between dying bees and overmedicating. Personaly, I believe that medicating sick bees is NOT the way to go. Why spend all the money to propagate inferior genes? Crazy! I am one of the "naturalists". I don't treat and don't plan to. If my bees get sick and die, I move on.
I think another problem is the people who want to breed bees that produce less propolis. Hmm.... Given the antibacterial properties of propolis, I'm not so sure this is a good idea. It's like all these corn growers who are genetically modifying their corn seed to repell pests and produce more kernels per ear. "Hey, Bob! That's a nice ear of corn you've got there. It tastes like crap, but you've sure got a lot of kernels on that ear!" I can see the same scenario in the beeyard. "Hey, Bob! That's a nice colony of bees you've got there. Too bad they're dying off, but at least they're propolising less!"
Some of this stuff just doesn't make sense to me.