Yes, there is obviously correlation of usage but I think most people are looking for a happy medium. I feel like I use my phone plenty and never feel like it is getting poor battery. But then again, this is all subjective. We also have the fact there are some bad batteries in fact some have exploded, and other phone defects are lumped in here too. We'll never really know but all we DO know is a) this phone makes you want to play with it A LOT and b) the battery is less than we're used to.
If anything, these companies churn out phones so quickly they could care less about fixing it and instead will focus on fixing new phones with bettery "more green" battery consumption, etc... It's time for some more innovation in this space, that's for sure!!
BTW, I think you're on to something with the 3G bit. Data over 3G seems like it sucks some major juice every time. Ditto with a long phone call, but maybe these are to be expected? Maybe not? *shrug*