Hi Greg,
Note I did say going forward from the IBM/Microsoft split
You could get MS or IBM branded OS/2. I have IBM branded OS/2 v1.1EE, v1.3, v2.0, v2.1 etc. I dont think I own an actual Microsoft branded OS/2.
I've been told that OS/2 v2.11 was the first version released after the split by some, and other IBMer's have told me that it was the last version that was a collaborative effort but still released after the official split. I do know that MS management had already decided that Windows was the way forward for MS well before they told IBM they were dropping OS/2 so reduced the resources allocated to IBM and OS/2. I got the impression that IBM themselves had to be hit over the head with a clue bat.
v2.xx's were still being produced with half hearted help and lack of enthusiasm from MS at the tail end of Microsoft's agreements with IBM. A lot of politics involved in v2.xx's. When IBM put more effort into it, as well as replacing more Microsoft code with there own was about the time they did there own confused marketing push. One part of IBM wanted OS/2 Warp to succeed, the other saw more money to be made supporting only MS-Windows. Being an ex IBM contractor I would have to say back in the mid 90's the money was certainly in the MS-Windows support on IBM (and other) hardware. There was little money to be made in pushing OS/2 compared to pushing MS-Windows. Bean counters ruled.
I believe it was this push that prompted the major release number increase as well as the term Warp.
I'll have to go looking through my old notes I had from Chuck Norcutt who died recently, and others to refresh my memory.