When OS/2 was launched it was a joint Microsoft/IBM product, and it was touted (by both) as being the replacement for Windows.
Exactly. I worked for a big corporate at the time and we all had PCDos on IBM ATs running stuff like IBM DisplayWrite and, most importantly, a mainframe terminal emulator because the (IBM) mainframe was where our serious stuff was. When Win 3.0 came out we were all handed boxed copies (I recently sold mine) - although Windows was MS, it seemed (to our management at least) the way to go, and was assumed to have IBM endorsement (a corporate essential) because it would run on IBM PCs. Management were unaware of the MS-IBM bust-up.
Win 3.0 was absolutely awful. It crashed and needed a reboot about twice an hour. It was soon replaced with the improved 3.1. It was not networked of course, but we would share printers in groups of four of us using a switchbox.
At about same time, one guy in our branch, our IT "co-ordinator" (who knew nothing about IT) was given OS/2 as a pilot. We all understood that would be the way to go fo all of us, but the whole thing stagnated (I guess because of the IBM/MS split). OS/2's price (its own, and that of the memory needed to run it) remained too high. I bought OS/2 for home but there were bugs (could have be sorted by IBM if they had their heart in it) and lack of apps. It seemed there was an anti-OS/2 camp within IBM itself.
But people, like our middle-aged management, who had never previously used computers (I had started on a PDP 11) or seen a GUI before, thought Windows and MS were absolutely wonderful. Us younger guys all had home computers by then, and knew better. Ironically, the generation after us also thought Windows and MS were wonderful because they never saw anything but Windows. It led to all the myths that we must now endure about Gates being a genius, inventing the PC, making computing affordable, and such like crap.
But Windows 3 (if we include its 3.1 bug-fix) was a milestone in that it popularised the graphical interface.