Like a lot of technology, once it's embedded into something important, it becomes hard to get rid of. But for 99.999% of us, it's a relic of the past (tense).
I'm not sure where OS/2 is used in production, today. I was surprised in the late 90s that the 2.x version was deployed at my first job more than DOS/Windows or Windows 95+ was. I remember finding out in the mid-00s that OS/2 was used in many ATM machines (and at one point may have been very common there)[0].
For most of us, it became past-tense when IBM stopped marketing it to consumers, later not marketing it to businesses and ultimately IBMs exit from the PC/server business. It's still alive much like AmigaOS is still alive. It died when large organizations, a lot of which were sold on the idea that it was "the next Windows" in the late 80s -- ones that believed "nobody gets fired for recommending IBM[1]" started deploying Windows 95.
[0] I'm guessing this is due to banks being large consumers of IBMs mainframe business, this didn't surprise me. The first company I worked at had a large liquid cooled mainframe that took up a floor of a datacenter, investment in COBOL programs/programmers and a whole department dedicated to supporting said device, its jobs, its software and its upgrades.
[1] This later became "Microsoft" but it originated, there.
Many archaic systems are not truly dead, I know of things still running COBOL77, but for all practical purposes we can describe them as 'dead'.