That just isn't close to being true. The ability to create a custom extension for use with OpenGL kept it very useful for a long time after Direct 3D had become the popular choice for PC developers. There was also code portability to consider,
1. Custom extensions mean one of the 3+ vendors can't use it, so they get minimal/no support, because it needs to run on all of them that claim to be complaint with version X, and that's enough work all by itself (unless the HW vendor wants to throw some extra money your way).
2. Extensions keeping OpenGL useful would be a textbook definition of a strawman. It has nothing to do whatsoever with what I wrote. DX allows for a more uniform set of client PC expectations, and has excellent support from MS. MS never set out to kill off OpenGL, and it's not going to go dying any time soon. They set out to make Windows and Microsoft console development easier, and to make income from that. DX's primary goals have been to make it easier for game developers on Windows (including MS consoles), and in the process they've dealt with some of the other issues of OpenGL, like lack of strong hardware requirements (but, they were smart enough not to specify implementation details).
3. How does OpenGL help you port between a x86 Windows environment and a Xbox360? Any other portability simply doesn't matter. If it did, then DirectX wouldn't even be an option, if coding from scratch. IE, if you have the choice between the two, you're generally either working on top of a licensed engine that can do either, or directly coding for Windows PCs. If you're concerned about portability to non-MS OSes, MS doesn't care about you, and DX is out of the picture.
In fact, I'll even go and use the end of your post for it:
Long term this may work out, but quite honestly the more iron fisted the control over a gaming platform, the more stable it tends to be(in terms of actual stability, development stability, consumer level stability etc).
OpenGL doesn't do that nearly as much as Direct3D, which is among Direct3D's benefits over OpenGL, in a Windows environment (OpenGL ES are exceptions, though).
obviously D3D was a profound failure on that front with *no* portability *even to Windows NT*.
Hmm? I've been gaming for over 15 years now on Windows NT, with DX versions from 3 through 11, and have only come across one game that could not be made to run (a console port, at that). If there were any oopsies regarding making D3D work on DOS-based Windows and NT, they clearly weren't anywhere close to being, "profound," because the games ran in NT, and in 32-bit, most continue to do so, today.
They do not set any industry standards. They do not create the development environment.
Actually, those are two things they actually do. Defining features hardware must support to claim compliance, along with minimum software feature support in drivers, and having major vendors agree to do it, is setting industry standards.
They have created the development environment, as well, since the mid 90s.
Neither point has anything to do with patents, though.