At the time I was (coincidentally) using NeXTStep at work and a BeBox at home, and I have a bit of extra perspective to add.

You are quite correct that NeXT was undoubtedly, upon close inspection, the ‘superior’ OS (UNIX lineage, stable, multi-user, etc.) but as a user (and sometime programmer) it wasn't that evident: my relatively cheap dual-604e BeBox outperformed my dual PentiumPro NeXT machine by a significant margin, or rather, felt like it did because the “pervasive multitasking” made the system extraordinarily responsive, and the lack of legacy code and backwards compatibility definitely kept the system snappy and lithe. Multi-user support didn't really change much from the user perspective either, as security was something of a remote concern and running any kind of ‘server’ on one's desktop was pretty exotic. BeOS was POSIX compliant to a degree such that many people still (erroneously) believe that it is a Unix or Unix-like, and you could run all the open-source command line tools you could possibly want. The BeFS filesystem's metadata capabilities were extraordinarily, and I liked both UIs equally (the etched vs. graffiti aesthetic legacy has etched itself into my neural circuitry), but probably NeXT was more innovative in terms of user interaction and rendering model whereas BeOS basically aped Windows and Classic MacOS quite closely. NeXT's development tools and environment were clearly superior. It was comparatively a resource hog.

So yes, there was a technical edge, and probably knowledgeable influencers at the upper echelons of power probably recommended as such. But at the time I had the feeling that Jean-Louis Gassée (the founder and CEO of Be Inc.) significantly overplayed his hand, and made ridiculous demands because he thought he had Apple cornered by virtue of their failed OS development attempts, growing obsolescence, and perceived lack of serious alternatives. There's the diffuse feeling that Gil Amelio (Apple's then-CEO) eventually grew weary of batting back the demands and started looking for apparent alternatives just as a means of introducing some competition to the negotiations, and eventually the plonked for NeXT much to everybody's surprise. He even made a droll remark about “choosing Plan A rather than Plan Be” or something to that effect. All things considered, it was a very counterintuitive decision, mainly because NeXT had such hefty resource requirements and we hand't quite yet absorbed the implications of Moore's Law (or rather, were used to Microsoft squandering any and all increase in hardware performance with increasingly inefficient code, leading to no perceivable improvement year over year). Amelio deserves more credit for having seen through all of that and made a brave, surprising, and obvious-only-in-hindsight decision that favoured a mature, stable, and extensible platform.

At the time I felt it was an utter mistake, but I was fourteen, and pretty ignorant of the ways of the world. I think history speaks for itself. Amelio deserves more respect for the decision he made, because it was ultimately his decision that led to adopting the superior, extensible technology, and of course brought Steve Jobs back on board (who promptly stabbed him in the back and ousted him in a boardroom coup).

I had a brief flirtation with Windows NT4/2000/XP in 1999-2003, but then I switched to OSX 10.2 on a dual PowerMac G4 and have never looked back since. Only of late have I started to feel that as Apple's focus has switched to iOS on mobile devices they've started to let their development effort and quality control really slip to borderline-unacceptable levels. I can understand that OS X is no longer the enabler for high-margin computer sales it once was, and that that role has passed on to iOS, but OS X (macOS of late) is the platform where the apps that form the bulwark of the iOS ecosystem get developed. Apple really shouldn't let the desktop OS languish or endure the kind of high-profile mishaps that have occurred of late.