Even with perfect hardware you will still have to reboot due to software instability. Lots of software isn't even tested to run for weeks/months/years.
That is just the Microsoft effect. Before Microsoft, anything that didn't run through the entire warranty period was returned to the vendor for your money back. And, you got it.
I'm also speaking of e.g. the junkware running on automotive headunits.
These systems are expected to be shut down at least once a day, so overall focus on (not only long-term) stability is really low.
Those came in post-Microsoft. Peak Microsoft was the US Navy ship dead in the water, towed back to port, because they had stupidly put MSWindows in charge of it.
The Therac-25 (https://en.wikipedia.org/wiki/Therac-25) didn't have a complex GUI. However, I hope that those affected by that bug did get their money back (and then some). Not that money can really help you if you get exposed to fatal levels of radiation, but...
GUIs do nothing more complex than many things that have to work right, so do. It is only tolerance for crappy software that allows it to be foisted on us.
I run xorg, and requiring X11 to restart is equally rare. Thus, I often go for months or longer, without a restart at the gui level.
If I get a browser update, I restart that, and so on.
Microsoft has conditioned the world to accept absurdity. Just the lost productivity alone, due to reboots...