FIFA interfere with the game enough as it is, can you imagine how much input they would want into a players contract if they were going to be forced to pay that players wages for a period of time during the year. They'd impose salary caps immediately, then we'd have all the mucking around with additional bonuses to top up those contracts, which of course the player wouldn't receive whilst on International duty. Not to mention the fact that FIFA don't do anything for free, so they'd be charging us for their input on top of their normal interference costs