1. In cycling hwere its all about endurance, increasing a heamatocrit level from x to y will give a person an edge over his equally fit and hard training rival. It is the difference between winning and losing.
Not so in football. A bit of extra endurance is perhaps a benefit - but it wont turn "donkey's into thoroughbreds" as it does (famously) with cyclists. It wont improve your touch, your footballing brain, your ability.
Agree with Irish_Cules.
That bit of extra endurance is pivotal in professional football, where a game can be decided by half a second or half a metre.
Also, doping isn't solely about endurance: It can also be used for heightening concentration, developing muscle mass, match recovery or recovery from injuries. It's multi purpose, and while it isn't the be all and end all, it gives a decisive edge; to quote Paul Breitner:
The footballer who believes that with doping he can keep his starting place, who can contribute more to victory, and can earn more money – why would he not use doping? The motivation to dope is the same for a footballer as it is for a cyclist.
And Breitner is correct. Even if a team/club isn't involved into systematic doping, what would keep a single player from doing it on his own out of personal reasons ? For example, Neururer accused many of his former players at Schalke of abusing Captagon while he was coach. Jens Lehmann confirmed it, while the club denied any knowledge.
Other than that, there's no need for a cover-up, simply because the detection methods used in professional football are borderline laughable, especially compared to cycling. And there's a reason for that.