Sky TV: Destroyed competition in the Premier League.
Gentrified the game by popularising it as a middle class sport so they buy the Sky packages.
Ticket prices in the Premier League are beyond the tradition client base of many clubs, which has somewhat percolated down into the football league.
It's now destroying the lower leagues as a spectator sport through its advent of the "red button". Despite United having some of the cheaper tickets, our crowds have dropped between one and two thousand this season.
Away games are increasingly difficult to plan. Cheap train tickets and hotels are becoming difficult to obtain, meaning travelling to away games is more difficult and less affordable. Most of these things negatively effect working class fans more; many of these fans see none of the benefits of Sky TV. These fans, and their antecedents, were the cradle of the game throughout the majority of its history, and created the "product" that is being stolen from them. Long term this is very dangerous: as football becomes less of a spectator sport, clubs will increasing depend on TV revenue for their very existence. TV companies will effectively run clubs. It has already happened in the Premier League. We're next, but our product has none of the gravitas of the PL, so are unlikely to survive and attract the same clientele.