Actually lately iPadOS is the one getting most of its features from macOS. iPadOS 26 introduced a menu bar, just like macOS, and a new windows manager that's just the same as macOS.
I expect it will happen within a few years after Xcode for iPad is released. MacOS is simply too open for Apple's business goals.
Or do you really think that all their apps and toolsets will run on whatever you are saying is the future of macOS.
"We don’t care. We don’t have to. We’re the phone company" skit perfectly applies to Apple these days ( https://snltranscripts.jt.org/76/76aphonecompany.phtml ).
A middle manager from Apple will easily toss all of Hollywood under the bus if it gets them a checkbox "shipped new toggle switch experience" and a promotion. And the upper management at Apple long since stopped caring about that.
Did you ever hear the tragedy of Final Cut Pro X? I thought not. It's not a story Apple fanboys would tell you...
As more MBP fundamentals are ported to iPad Pro, that will naturally convert more Mac users to iPads, especially the iPhone generation.