I'm very happy that Steve is such an Emacs fan. I have little doubt that the Emacs support will be top notch when this hits the street.
I with he were more knowledgeable on IDE's (IDEA, Eclipse, Visual Studio, XCode) so he had a better idea of what modern developers expect from their tools.
I'm hoping Grok will succeed, but I wouldn't be surprised if in the coming year, it gets completely canceled.
Also worth noting: he is pretty knowledgeable about IDEs too. Why do you think he isn't?
Finally, I wouldn't count on Grok being canceled.
"IDE as a service" in the style of Grok (or Ensime for something currently available) puts Emacs on a level playing field with any IDE.