Linux is only a tool, just like the hardware it runs on. I have to say that Windows, as a tool, had roots in Fisher-Price.
Linux is extremely versatile, doing anything from large clustered multiprocessing to simple embedded machine logic control. That flexibility must remain.
It will be in vendors best interest to maintain kernal level compatibility and more. Remember IBM's micro-channel buss? Fantastic buss, DOA. The market will play a big part in keeping the vendors in line. We simply won't buy it without compatibility.
However, any standard that is set must be flexible enough to qualify both small industrial versions all the way to large clustered servers. I do not believe one standard can cover this wide range ofuses.
In other words, there probably must be different flavors of kernal to continue it's growth among all segments of computing.