Open is already relative
With Linux embedded in Windows, "open" is already a relative concept. "Proprietary open" meaning they tell you just as much as they think is safe while protecting their IP is probably the realistic future. Ironic as the predominance of the IBM PC was entirely due to it's being mandatorily an open standard. The manual that came with my first PC included full circuit diagrams and BIOS listing. That openness directly drove both PC clones and the huge add-on industry that put the current closed source big players on the map.