Aren't VTOL aircraft significantly more complex and riskier to operate than fixed-wing prop aircraft? There's certainly many fewer moving parts and tricky transitions from hover to airfoil flight regime.
And there’s that whole pesky problem of not being able to glide to a safe landing when something goes catastrophically wrong.
A quick search of Osprey Class A mishaps puts it slightly ahead (better off) than Blackhawk or Super Stallion.
But a way worse record when compared to the fixed-wing C-130.
Both comparisons are per 100k flight hours.
Some of that risk can possibly be mitigated with a rotating engine, but fixed wing, similar to the Bell Valor. Possibly, because AFAIK, the Valor is the only plane like this and it's just a PoC.