OS/2 was a true multitasking OS, vastly superior to Windows 3.1, which had no process protection. OS/2 had a Windows 3.1 compatibility mode that was more stable and reliable.
What killed OS/2 was IBM’s total indifference to developers and marketers. I wanted to write a device driver for OS/2, but IBM wanted something like $10,000 for the Device Driver Kit (DDK) and another $5K or so for the compiler.
In contrast, Microsoft gave away their Device Driver Kit (DDK) for free with a compiler thrown in. And they gave great marketing support including a hardware compatibility program that granted hardware vendors the right to use the Windows logo and artwork in ad copy to sell Windows compatible hardware.
So all the hardware vendors (including mine) turned their backs on OS/2 and embraced Windows. This despite the fact that by any technical measure OS/2 was the superior platform by far. OS/2 had a 100% compatible Win 3.1 subsystem (IBM cross-licensed their source code with Microsoft). So a device driver written for OS/2 would also support Win 3.1 apps.
If IBM’s management weren’t such idiots we would be running OS/8 today instead of Windows 8.
See #19.