The fact that Chelsea can go and buy whoever they want is just the way of the modern game.
Any capping would have to be voluntary, as restrictions in trade would come into effect.
Get real Mr Whelan, if it happened, sponsors would re-think their capital outlay into clubs and competitions.
There would be a reduction in money coming into the game and you woul be affected.
Look after your own club and leave the rest to look after theirs.