I think this conflates two different eras/layers. NT 4 famously moved the window manager/GDI/graphics subsystem into kernel mode, so that’s probably the “opposite direction” history. But modern GPU-driver recovery is WDDM/TDR, and it very much still exists: WDDM splits the display driver into user-mode and kernel-mode components, and TDR resets/recovers a hung GPU/driver instead of requiring a reboot.
I also update NVIDIA drivers regularly on Windows 11 without rebooting, though that’s install-time driver reload rather than exactly the same thing as TDR.
And I don't recall any practical way to recover from a crashed NT 3.x GUI subsystem.
It would presumably still function as a server, and be gracefully shut down remotely, but in the absence of anything like Remote Desktop or EMS[1], you'd be hard pressed to get much local troubleshooting done without rebooting the system anyway.
Also, as an NT user since 3.1, and a daily user of 3.5 and 3.51, I don't recall the GUI ever actually hanging or crashing (other than as a side effect of a bugcheck, which, by definition, is a crash triggered by code running in kernel mode).
That's one of the main reasons I was an early and enthusiastic NT user: while I can't say its performance was any better than "good enough", and then only on hardware that was at least comfortably above average in terms of CPU speed and RAM capacity, it was remarkably stable compared to every other PC OS I had used at the time.
Which, to be fair, would have been limited to MS-DOS, 16-bit Windows 2.x and 3.x, and OS/2 2.0 at the time, though it remained true throughout the lifespan of Windows 9x and OS/2 (at least through 3.0, the last version I used), and neither FreeBSD nor Linux were as reliable once you added at least a basic X11 environment to reach rough feature parity (and while X11 did allow recovery after crashing, insofar as it can be restarted without rebooting the system, it still took all your GUI applications and xterm windows down with it when it crashed).
https://learn.microsoft.com/en-us/windows-hardware/drivers/d... https://learn.microsoft.com/en-us/windows-hardware/drivers/d...
I also update NVIDIA drivers regularly on Windows 11 without rebooting, though that’s install-time driver reload rather than exactly the same thing as TDR.