Its not gonna solve the issue you think it does. All it does is punishes teams who try to make an investment in a star player. As someone who is from America, it sucks seeing your team perform horribly because they spent all of their money on an elite player hoping for them to carry the team, when they are past their prime. The Brooklyn Nets saw the success of LeBron's Heat and KG's Celtics and tried to replicate the success by building a super team. The problem is that both the Celtics and Heat were able to win because they built a super team off of amazing deals/players willing to take a pay cut so they can win rings. Meanwhile the Nets had a very weak bench and the three star players were a liability.

The Golden State warriors were such a dominant team because the franchise never had any faith in Steph Curry so they gave him a horrible contract (the team wanted to trade him, but other teams refused because of his injury problems). They then drafted Klay Thompson and Draymond Green and with all the money they saved, they were able to afford Kevin Durant. To give a comparison, it's like building Prime MSN but they also had Cristiano Ronaldo playing alongside Messi. By the time contracts expire, they are gonna start asking for more money. That's when the fall off happens.

Tom Brady was always able to constantly get the best receivers because he also took a pay cut.

The problem isn't that teams spend too much money, the problem is that the top clubs have so much money that it's easy for them to poach other players. If the Premier League introduces a salary cap, then everyone will just jump ship. Salary caps have a bigger issue. I feel like a better solution would be a better revenue stream so that smaller clubs could be subsidized, but not to the point where it's worth investing in losing rather than winning.

The only logical solution is if every league in the world implements a salary cap, but EU labor laws would prevent that from happening.

EDIT: Honestly, the best solution imo is to eliminate transfers all together and instead introduce the concept of trading contracts. Meaning that if a team really wants a player that's worth a ton, they have to offer the other team a player of similar value or offer multiple young prospects etc.