Marine Air is growing, we have *new* squadrons standing up. there is going to be a need to fill cockpits.
I think a more accurate statement is that Marine Air is getting younger. It started earlier this decade with the J-model KC-130 followed by the Osprey. The New Huey is flying and the new Cobra is not far from the fleet. When the JSF and the -53K arrive we will have a relatively young fleet of aircraft compared to the other services.
When the drawdown begins, I can't really predict what will happen other than flight students will find it more competitive to get their wings and those in the fleet will find it harder and harder to get back to the fleet