You can look at the draft/salary cap regime vs. relegation as two ways of encouraging competition. It's really interesting just how different the system is for Euro soccer than for pretty much all American pro sports: relegation/promotion, no draft, no playoffs, no salary cap, player sales rather than trades, no transferring of contracts (a player negotiates a new contract for a transfer), hardly any relocation of franchises, youth systems rather than college sports, etc.
All sorts of historical/geographical reasons for that, which probably also explain why Euro soccer teams can't blackmail their home cities with the threat of moving (way more densely populated with teams than US sports; there aren't any big unserved population centers like there are in the states). And yeah, stadium subsidies are BS.