I find this a little unlikely. Many of the 360's exclusives were only timed or went multi with later installments, plus I don't think EA will be able to resist the lure of more than twice the install base to sell to.
It is true that a big enough moneyhat could in theory tempt EA to leave it where it is, but as has been pointed out keeping hold of such an enormous game (and say what you like about it, TF is extremely likely to be one of the gens biggest games, IMHO) would be enormously expensive for MS and unlike Gears, MS aren't the publisher so they have less influence over what happens with Titanfall
I suspect the deal was made before it became apparent that this gen seems to be swinging to Sony at this very early stage, had they known I think EA would've hedged their bets and gone multi from the beginning. It makes sense - COD and BF all sold best on 360 and until MS started making umpteen PR disasters and revealed the price, there was little reason to assume that that would change this gen, but when it did EA were caught in this slightly awkward position







