Plus Windows ME wasn’t exactly nimble either. People talk about the disaster that was Vista and Windows 8 but ME was a thousand times worse. Thank god Windows 2000 was an option.
Also, at the time NT was still somewhat limited in official settings to pretty much rare more expensive places and engineering systems, with typical business user keeping to Windows 98 on "client" and NT Server domain controllers or completely different vendors, at least outside big corporations with fat chequebooks. Active Directory started changing it a lot faster, the benefits wer great and 2000 having hotplug et al was great improvement, but it took until XP for the typical office computer to really run on NT in my experience.
I think the main difference is really just that XP had a “Home” edition that came preinstalled on home PCs.
There’s no reason Microsoft couldn’t do that with 2000, and in fact I read that some stores did stock Windows 2000 instead of Windows Me (though this wasn’t something I personally witnessed).
From what I recall, an important point for releasing ME at all was that compatibility (both in applications and drivers) was not yet ready at the time of NT 5.0 going gold, leading to a stopgap solution being deployed.
I guess it depends on the office though. At risk of stating the obvious: Different organisations will do things differently.
The organizations that really needed NT for various reasons (engineering software, SMP, higher security settings, etc.) did move as early as NT4, indeed. Also, non-trivial amount of Alpha workstations with NT4 (as well as Pentium Pro ones)
But yeah, what a turd of a system.