When I gave up on Mac over 8 years ago, it wasn’t a financial decision. A you note that iPad can do 90% of what a Mac does (for you), and as you already note that iPad is so much more portable and versatile, perhaps you don’t need a Mac either.
1. To actually be productive for a long periods of time you need the biggest of the iPads. Anything smaller than that is gimmicky for the purpose.
2. Portability for me is not the same has needing to hold something in my hand. Let's be real, it's a pain to hold the iPad 12" o the hands even for browsing for more than 10 minutes ... just the strain in your arms ... after a min or two you are supporting it with your belly. Ok you can put it on table but then look at your posture.
I'm here in my MacBook Pro 14" writing this post in the couch totally comfortable, no strain in the arms. Look I can even browse with just one hand typing and click while the other is a holding a glass filled with scotch.
Ok ... now you buy the Magic Keyboard bump in cost. It got much better, true. But now you have something in the backpack that is almost has heavy and thick as a MacBook Pro. Worst, something cumbersomely pretending to be a MacBook Pro.
3. Versatility. Well the iPad Pro + Keyboard + Pencil as the potential of being more versatile , but such is implementation is totally unbalanced. As far as productivity go, pencil and touch are good for simply 10%-20% of productivity tasks ... unless you spend all day taking notes and drawing. For 90%-80% the keyboard and trackpad pad is way better.
But here is the rub, the entire thing is built on the strengths of touch and now pencil, that is to cover the 10%-20% of the productivity tasks. That is why Apple needed to bring in the keyboard! In other words, the iPad OS is a platform optimized for 10%-20% of productivity tasks ans relatively cumbersome on anything else. while macOS is optimized to 80%-90% while potentially cumbersome on those 10% to 20% of productive tasks.
Being different and looking great is not necessarily a good thing.
Now if Apple granted the MacBook Pro the ability to borrow touch and pen from the iPad for those 20% of productivity tasks that actually would take advantage of this ... I would say it would be a more balanced approach. Its is just a matter of Apple giving the MacBook Pro the ability to borrow touch and pen from the iPad as the later borrowed keyboard, trackpad and mouse from the first.
4. I don't see any reason why the M2 or M4 on a iPad Pro form factor could not handle Mac OS. I bet Apple has macOS 🏃♂ great somewhere in the R&D. Even without changing macOS UI! Guess what it even runs iPad OS apps!!!!! They probably call it the MacPad, MacTouch or whatever.
Cheers.
PS: I have years of experience trying to use the iPad Pro 12" for productivity. I really wanted it to succeed. But the M processors arrived to the Mac and boooooom! I purposely left behind my MacBook Pro in the office when traveling for business multiple times. I love it for meetings and laying in bed, but anything else shush. I am also an amateur street photographer ... really liked to use Affinity Photo to edit photos for a while with a pen ... but any other photo editing tasks the MacBook Pro was much better ... it does not make much sense to transfer the Photos to the iPad when I can simply edit in the Macbook as well.
I agree, the iPad Pro does look extremely cool. It gives a wow impression. But if you get past that and start to rationalize and not be willing to put up with its idiosyncrasies - why are iPad users being forced to use a Windows Manager that operates like it has been design by a 3 year old? etc etc etc. Then you start to question your efforts to make it work for those 80% of the tasks with no friction ... is it really more evolved then macOS? Or is really dragging its feet to be something that already exists just for the sake of being different?
Then you ask. Why am I really rotating the entire house to screw a light bulb (touch & pencil)? To use my fingers?