If they had released an M3 iPad Air and M4 iPad Pro at the same time then yes I would agree with you but putting a chip that’s already 2 years old into a new iPad Air is not on.But, for those that want the Pro, Apple actually sells a product specifically for them. The iPad Pro.
For those that want the Pro, but want it to be named “Air”, yeah, nothing for that crowd.
This is precisely why they need to go back to an annual spring event in March where they update all their iPads at the same time every year.