I know you have a wage cap (last I heard), but surely Shamrock Rovers will, with their new found riches, be forced to pay over the odds for a few players in an attempt to "go to the next level", and those teams will stay in business, develop players, buy players etc.
As long as they don't do what City did which is cause the wages to go to stratospheric levels and completely undermine all the good they do buy spending a lot of money on players from other clubs (when those clubs then have to raise their wages to challenge), then the other clubs will benefit.
Of course you're probably going to tell me that unlike the leagues I watch, 90% of the clubs running costs aren't because of players and cannot be recouped from selling players either.