As an Australian I genuinely find European football salaries obscene and a bit disgusting tbh. Over here both of our major codes of football, NRL (rugby) and AFL (aussie rules) have had salary caps since the late 80s. It's not something implemented per player, but instead for the total roster of a club. The point is to make the competition fairer and well, more interesting, because you don't have all the good players concentrated into a few super clubs. In 2022 it was $13.5m for AFL clubs and $10m for NRL clubs. As well, if you breach it you generally don't get to earn points on the ladder until the following season. If you did it in the past, won a premiership and it's discovered, the title will be stripped.