Left after serving about triple the ROSO of when I joined.
Money? Sure that played a part.
Lack of future flying? Nope, didn't have a ground job, flew the whole time and frankly was looking forward to a little break. Had been offered future flying jobs - in fact looked like flying for another decade ish but it played no role at all in our decision.
Ridiculous mission creep on extra requirements for deployment and general service "currencies"? Yep, very annoying taking up such a significant amount of time that doing your job to the standard you expect of yourself became impossible.
Lack of experience in units acquiring new aircraft? Frightening. To say the least.
Moving around? Absolutely a factor.
So, like most people, a combination of factors added up to a decision. Everyone will have their own combination and make a decision.
Can (or will) the government afford to keep people in? I don't think so. Can they afford not too? I know they will do everything within their power to get away with it as cheap as possible. The DOD got away with some things after the events of 2001 (with respect to pilot retention and recruitment). It looks like that is now going to cost the Defence Force. Big question is, what price will it pay? I fear it may be more than loss of operational capability.