My only guess is they have a parallel skunkworks working on the same thing, but in a way that they can keep it closed-source - that this was a hedge they think they no longer need, and they are missing the forest for the trees on the benefits of cross-pollination and open source ethos to their business.
This brings back memories of late 90s / early 00s of Microsoft pushing hard their proprietary graphic libraries (DirectX) vs open standards (OpenGL).
Fast forward 25-years and even today, Microsoft still dominates in PC gaming as a result.
There's a bad track record of open standard for GPUs.
Even Apple themselves gave up on OpenGL and has their own proprietary offering (Metal).