I have a sneaky suspicion you may be grouping things that you don't like and aren't interested in, and calling them 'mainstream'. Yes, there is a lot of football on the telly and in the press, but I'm not convinced that 'being on the telly' = mainstream.

I think that football fans are extremely tribal. You do get genuine enthusiasts of 'the beautiful game', but not that many of them. On the whole, people watch their own team, plus England games, plus (sometimes) other people's games that might impact indirectly on their own team's fortunes.

Therefore, if you are going to broadcast football, you really have to show a lot of it, because most of the audience is only going to be interested in a small chunk of what you show and the rest will be irrelevant to them.

I don't think you can compare it to computer gaming, because computer gaming is a participation sport, not one that is specifically designed for small numbers of people to play and large number of people to watch. Furthermore, football is a long-established hobby which has traditionally been covered by traditional media: I suspect that in new media, the amount of coverage is reversed.