A poor start and cost
Admittedly, the first two major releases were both costly and crap but Warp was a far better piece of software than any DOS-based version of Windows. Basically, customers expected an OS that was free (or its cost was covered by the inclusive deal). OS/2 was always a costly extra and, by the time it was any good, customers had bought big time into Windows 3.x The insistence on loading the registry into already restricted RAM made Windows 95 inferior to 3.x in my opinion but Microsoft's huge marketing effort made folks want the shiny and new. Luckily for me I was able to go from 3.1 to 2000 via Warp 3 and 4. Before anybody asks, yes, I had lots of compatibility issues with 2000 but not one that couldn't be solved.