At the time, if you had a powerful system, it felt so much faster than Windows. OS/2 Warp had much better multi-tasking support at the time as well and it felt much more crisp. Windows was the default, but it was also really mediocre at the time.

macOS still uses Objective-C, and in spite of Swift love, some key frameworks (like Metal) make use of it.

The new C++ userspace drivers is called DriverKit, most likely in homage to NeXT Objective-C based DriverKit.

DisplayPoscript has evolved into PDF.

WebObjects has transitioned to a Java based framework, that is only used by Apple, and was the basis for J2EE design. Other than that even less people used NeXT for servers than workstations.

EOF evolved into CoreData.

If you want Renderman it is still available.

The UNIX underpinnins never really mattered, in a MIcrosoft kind of way, its main purpose was to bring UNIX software into NeXTSTEP and be a checkpoint on contracts.

So for me it is pretty much alive.