Corruption does not need to be about money changing hands. Ferguson used to rant about decisions given against the Rags. Every Referee knew that if he ranted about you, you did not referee again at the Swamp. If you are a referee you want to be doing the big matches, United against Liverpool/Arsenal/Chelsea. So you comply, you do not give a decision against United. No money has changed hands but it is still corruption because you are not acting honestly, you are acting in self interest and yet it was allowed. No one questioned it because a succesful United meant a succesful Premier League, a succesful Sky a succesful everything because everyone made money.
If Sky want to sell a match to the far east, the Rags v Liverpool would always (for now) get more money than City v who ever. It is about how you make money. You need to keep the rags relevant. PiGMOL want to be part of that as the Premier League has pushed them into the big money so they just tow the line and do what they are told.