Raw resolution matters a lot less than PPI and contrast/color quality, IMO

On a phone yes, on a "desktop" OS losing resolution often also means being able to display less stuff.

In 2022 scaling mostly works.

I have a 4K screen with Windows 10. Some apps look great, some have really blurry text, some have really tiny UIs (or a comical mix of tiny and normal sized). This last category includes much of Windows' own UI...

Not in my experience.

is that not enough for a 17"?

I don't have that many on my 27" desktop monitors and it's totally fine.

That's completely fine.

Sorry, I should have clarified what I meant.

I meant that 4:3 17" is substantially more than a 16:9 17" monitor.

4:3 vs 16:9 for the same diagonal (17") results in 12% more area. a 16" MBP is already large, and is only 16:10, so 17" 4:3 is comparable to like 18/19" of work space in 16:9/10 world.

Scaling settings matter a lot more than just resolution