IBM also made a whole bunch of strategic mistakes beyond that. Most importantly their hardware division didn't give a flying f about OS/2. Even when they had a 'better Windows' they did not actually use it themselves and didn't push it to other vendors.
Windows NT wasn't really relevant in that competition for much longer, only XP was finally for end consumers.
> where nvidia has the standard that AMD is implementing, and so no matter what if you play in the backward compatibility realm you're always going to be playing catch-up
That's not true. If AMD starts adding their own features and have their own advantages, that can flip.
It only takes a single generation of hardware, or a single feature for things to flip.
Look at Linux and Unix. Its started out with Linux implementing Unix, and now the Unix are trying to add compatibility with with Linux.
Is SGI still the driving force behind OpenGL/Vulcan? Did you think it was a bad idea for other companies to use OpenGL?
AMD was successful against Intel with x86_64.
There are lots of example of the company making something popular, not being able to take full advantage of it in the long run.