I don't think any sport is as morally bankrupt when it comes to cheating as football, so it does seem "surprising" that no one ever gets caught using PED's. When you've got nations helping fake the age of players, people diving all over the place, holding their face knowing that they are on camera and that everyone will see that nothing touched their face, bribing and threatening referee's and just about every other kind of cheating going, it seems incredibly naive to think that PED's aren't absolutely rampant, especially given the incredibly lax drug testing in football and the amount of money at stake.
Hopefully we'll get a baseball style inquisition and the truth will be uncovered, with all the hilarity that brings.