I'm not so sure it's just an aircraft issue.
It isn't
just an aircraft issue, but the aircraft readiness certainly doesn't help. We absolutely flew the wheels off the V-22 fleet throughout OIF and OEF, in addition to stuff like SPMAGTF-CR-AF (and now ACE-CR-AF) which, while low intensity, involves a ton of long-range transit. We basically broke the macro-level phase tree for the whole T/M/S, and the squadrons started really paying for it circa 2020. Material management, in true Marine Corps fashion, was punted hard and it led to things like squadrons having 15-20 aircraft on the books while still being staffed for 12 aircraft. Oh, and depending on the timeframe and the MAW to which you belonged, you had to cancel your flight schedule if you didn't have at least 50% PMC. Weekends and 12 on/12 off galore.
So it became a personnel issue, too. We are hurting badly for qualified maintainers in the fleet because they're treated like garbage and constantly forced to do more with less. Single E-5s with their WTI patch and CDQ stamp being forced to live in the barracks because they didn't wife up the first stripper to give them the time of day.
Meanwhile, the FAA decided V-22 time counts towards all the Airplane ATP minimums except 50 multi-engine (which we get in Advanced anyway), so now the vast majority of pilots north of 800 hours just dip out because they can at least get on with a regional. Pay cut, sure, but the better deal compared to being an overworked Department Head. Which is how we're now getting O-4s from the HMLAs and HMHs assigned as VMM DHs.
Unless you're the super-stacked MEU squadron on your respective coast, you have 3, maybe 4 NSIs/WTIs giving advanced T&R codes. Just not enough to feed everyone and it burns those guys out, too. Doesn't help that some squadrons also have mid-level instructors outright refusing to fly because we've had so many high-profile mishaps in the last 2 years and now they don't trust the plane.