A long time ago, there was no bonus prize when winning a Cup game, there was attendance revenue. It was 50/50 for both team.As you can see, it was changed. Small teams were hoping to draw a big team and away game. Basically, they were hoping to lose and get big money. They could be unlucky and draw a big team and receive them. Elimination and small revenue. Then there was the big teams playing between themselves (or slightly lesser good teams) and getting eliminated while other big teams were having five games in a row at home against bad teams. With today's revenue, that would be more than one million in 5 weeks compared to teams getting 300k$ or under.The best teams would get a lot more money than now and that would be an advantage over the small teams trying to reduce the gap. Not close to the reality, but as game play, I think the change was for the best. And that was even less unfair than what you are proposing.
I don't remember when that changed.