This is so naive. Footballers are bigger, faster and stronger than they have ever been. The game is played at a higher pace than it has ever been. Top footballers play upwards of 60 games a year, yet you think that something that allows you to run more, and recover faster would make no difference? Footballers need a high degree of natural talent to make it, of course they do. Therefore, do you think the best cyclists and athletes in the world were just talent-less bums who started taking EPO then could win all the races because of that? Do you think Lance Armstrong was just some fat kid from Texas who stumbled across a guy selling blood boosters, bought a load then became the best cyclist in an era of cheats?
Read this http://www.theguardian.com/sport/2013/jan/29/operation-puerto-doctor-footballers-fuentes and this http://www.telegraph.co.uk/sport/othersports/cycling/10027763/Operation-Puerto-judge-sparks-outrage-by-ordering-destruction-of-blood-bags.html. Now think about the high energy pressing game favoured by Barcelona and the Spanish National Team. It isn't conclusive proof but it is mighty suspicious.
I do think you need to take in consideration the newish view on the footballing diet on the speed of the game and the fitness levels.
It was not that long ago that players ate and drank what they wanted.
how often do we hear players are suffering from playing to much?
over the Christmas period you see a dramatic drop in the standards of games by the third game.