I can't see either of them leaving KTM, they both know they are on to a good thing with the support and bikes KTM prepare. Despres was heavily involved in developing the 690 Rallye bike from the start, so it's almost his bike.
They ride in different teams with different sponsors so it will only make them even more keen to beat each other. Everyone in the team will want to beat their shared enemy, leaving KTM in a win win situation. There has been plenty of rivalries in the Dakar before, Peterhansel used to get so annoyed with the other riders following him and not navigating, that he deliberately went the wrong way and then faked mechanical problems. With the others now lost he would wait till they had left him and would Navigate back onto the right route.
KTM 540 Rallye
KTM 300 EXC