Apple has made some bad choices with iPadOS that they were pressured into making by this vocal minority that keeps insisting that somehow the tablet is the form factor of the future. Maybe they've seen too many movies, I don't know.
iPad was fine the way it was, without Stage Manager and without many other pseudo desktop features.
But iPad has also been replacing computers for people who don't really need computers since the day it was released in 2010. Each successive model and update that adds a new feature grabs at a new group of users who no longer need a computer. So they probably want to keep that trend going, since it has worked from the beginning. What they do not need to do is even attempt to replace the Mac entirely with the iPad, because that's simply not possible. If you dual boot an iPad into macOS, you now have a Mac that's too small to be a Mac, hardware that's not up to the task of even the most low end MacBook Air, and mandatory keyboard and mouse input since macOS is not a touch OS. That doesn't get anyone anywhere.