Because this is a 4k console in 2020, and all the marketing says it's the world's most powerful console that is focused on 4k. Obviously the UI is 1080p by choice and not because they can't do it or that it doesn't have the power. Like I said in some other thread, if they want to free up more RAM resources they should have just added more ram dedicated to the UI, it's like the most basic stuff and bare minimum that I would expect.
To me, it detracts from the overall quality and package and is seriously detrimental to the overall presentation. Of course I would never base my console choice on something as silly as the UI or the UI resolution, but I think it's as embarrassing as it's unacceptable to not render the UI at native 4k for this kind of premium 4k product, and with that kind of marketing that they have.
Just the fact that PS4 pro does it makes it even more embarrassing, and I'm baffled that even the X1X doesn't render the UI at native 4k. So.. I don't know if it's a "big deal" and it wouldn't put me off buying either console, but it's fucking stupid. And it has nothing to do with console-warring.
I'm even more astounded that the Switch UI renders at 720p in TV mode, but then again nobody should expect anything by Nintendo when it comes to resolution but.. yeah in 2020 it's just beyond unacceptable to me. Like I said, it's just bare fucking minimum.