I look at it completely the other way - why would Loeb not leave PSA now?

If there was any so-called loyalty Citroen basically tossed the guy that made their motorsport brand to the kerb. Once the Dakar is done, unless Loeb wants to do a few small rally raid events and play second fiddle to Timmy Hansen in WRX then he's going to need to do something else. If you read up on the situation, and Loeb's comments printed today, then you'll see that he can't just waltz between the two PSA brands, even if they do share a facility.