Craig Federighi has sought to explain why Apple cannot bring Stage Manager support to iPads released before 2021. Supposedly, iPad Air and iPad Pro models from two years ago are simply not powerful enough to run Apple's new multi-tasking software, which are only possible with the Apple M1 chipset.https://www.notebookcheck.net/Craig-Federighi-explains-Stage-Manager-exclusivity-in-iPadOS-16-to-Apple-M1-hardware.628530.0.html
The base M1 iPad Air doesn't get Memory Swap because it would use to much of the tiny 64GB storage but still gets Stage Manager!
Apple is just making up excuses and the only reason is they want people to get rid of their functioning devices to buy a new iPad. All that while claiming to save the planet and caring about the environment.