"Revolutions" in the industry are often not the result of a big bang, but more frequently of mere accumulation of little steps. GNU+Linux has not changed anything in the industry when initially released. It was years (decades?) behind current techs at this time (but has fast taken leadership in many areas), and at first only used by hobbyist, then only used for applications with simple needs on simple hardware as a cost reduction measure, then used in more areas and so over.
And I'm far from sure that the decisions good for the long term development of Linux would be done by bigcorps if Linus went missing anyway (especially not Google). Bigcorps have bad habits (with high impedance mismatch in the context of the Linux project), like development behind closed doors, and not only time-to-the-market centered but even for some of them time-to-the-market weighting 95% in their choices. Because of that, bigcorps were the cause of the arm branch mess in the first place. Bigcorps often lead big projects that fails big. And Linux is not lead by bigcorps anyway, it's lead by peoples.
Also, the same argument could be applied to lot of people in leadership positions anyway. Maybe Apple would not be Apple without Steve Jobs, but the CEO does not matter more in lots of big companies than Linus matters for Linux. Maybe it would be very equivalent with somebody else, or maybe not, but in the meantime they are in charge, and when they do a good job, they are the ones who matter.