There is a non-zero chance that football as we know it won't exist in 5-10 years. As more cases of brain damage come out, the NFL, NCAA, and junior leagues have no way to further protect players and there may be rules changes that either maximize safety and impact popularity and/or drive advertisers to other sports. There will always be football in the US as long as there are advertising dollars supporting it but it may not look much like the 2011 NFL.
Steroids were/are a real problem for baseball, but they are in no way as central to the game as hitting is to football.