My take on why OS/2 didn't become the standard is that most peoples computers back then wasn't big enough to take advantage of OS/2, unless you were a high end user of sorts putting OS/2 on your machine would essentially drag it down as you did not have the RAM and the CPU power it needed.
The reason as i recall is much more simple. Consumers followed the herd instincts. Computer magazines had some nice things to say about OS/2, but critically they never called for the masses to adopt it.
Before Windows 95, there wasn't so much of a personal computer demand for Windows OS or any other OS. Most machines people had in their homes ran DOS and kids played games on it while grown ups maybe used WordPerfect or something like that. Plus those machines were quite expensive. Same is true for laptops of the day.
I think it was far more likely that a personal computer was an Apple. Or a "cheap" XT or 286.
OS/2 competed with Windows 3.11 for office computers. It wasn't an economical solution so it died off or was killed off.
For gaming, it was a toss up between Nintendo/Sega, and DOS, with an occassional Amiga 500 or ageing Atari ST in the mix.
Once Win 95 launched, Microsoft marketed not so much the OS for OS sake, but instead pointed out how the information superhighway is here and it was time to get on board. Also, plug & play debuted around that time.
This was the serious beginning of PC mass appeal (and PC annoyances and troubles for the masses). There was so little point in even trying anything other than Windows, unless it was curiosity.
If you were going to have a PC, you were going to run Windows on it.
As for the advantages of OS/2, it reminds me a little of how the Amiga Workbench 3.x had many advantages over Win 3.11 and Win 95. Things like custom size icons, separate selected and unselected icons for the same file, window backgrounds (Microsoft later adopted and abandoned this idea around Win 98), hiding unneccessary files by default, and other features i can't really remember anymore.
Of course the Amiga hardware was at a huge disadvantage compared to modular PCs, and the company was mismanaged into oblivion, but you may still find old fans reminiscing over that OS.
Point here being that even if an OS is good and better than a rival, it has to be a killer otherwise the masses just will not take it up. And without that it becomes a niche OS that doesn't run on a huge number of machines.
Also, it should definetly not crash as much as Amiga Workbench did.
Whatever you may think of Apple's modern OS, there are enough people who will swear by it (plus Microsoft never stops dropping the ball so there's that too), and this never happened with OS/2.
That OS had also ran written all over it in every article i've ever read about it.
So i disagree because i think back then there just wasn't such a thing as a high end user. Not in the sense there is today. High end users or power users kinda begin with Win 98 second edition or even XP.
The business professional crowd couldn't be lured on board in time so that was that for OS/2.