I was once told “if you ain’t cheating you ain’t trying”.
Both rugby and football are played by professionals who know how much bending of the rules you can get away with. They know because they’ve been playing for years and they had the same tricks pulled on them when they were young players, and watched the perpetrators get away with it. So they take that trick into their repertoire and then learn a few more, and the level of cheating creeps up over time. Similarly the new refs see that their older counterparts are choosing to ‘interpret’ some events as being acceptable and so learn that this is how the game is played, no matter what the rules say.
IMO the main difference between rugby and football comes down to being cited after the event. The video ref system works well in big rugby games because there tend to be more contentious issues than in the typical footie game. I can see that it’d be a big investment that rarely got used for football, but citing would be cheap and effective, especially if backed up by recordings from a mic’d ref.