So maybe there should be and maybe there shouldn't. It's a business. It's supply and demand. Is the issue that the clubs can't afford it or is it a moral crusade (see Nurses etc) ?
Take the organised cartel of American football.
Their players generally get more in wages that the top premier league stars. A lot get signing on fees equivalent sometimes to transfer fees. Owners get a real wedge guaranteed for life. It's a massive set up that is only attractive to one country (biggest economy, of course). It also supports a massive behind the scenes industry.)
Make no mistake, if it is not introduced world wide, it will be undermined - probably by the yanks!
There is a superb documentary about how in reality their pay is shit compared to baseball, Hockey and Basketball.
The truth is that whenever the yanks are involved in the running of a sport, the prices go up, the sport becomes performance art, the owners get rich and the players are often collateral damage.