> What does Elon know that Google as a whole doesn't?
It's not what he knows per se, it's what he does, it's the source of his motivation for being and doing.
It's that invention and innovation is most often driven by individuals - whether acting together or in solitary - in pursuit of something that matters to them. You saw this throughout the industrial revolution. You saw it at Bell Labs and Xerox PARC. You saw it with regards to the individuals that pushed the Internet and tech universe forward, from Ted Hoff to Dennis Ritchie to Tim Berners Lee.
It wasn't a giant corporation and team of 100 people that created Doom and Quake. It was a tiny team of highly motivated people doing something that mattered to them. That same conceptual story frequently occurs throughout modern history.
Elon Musk desperately wanted (wants) to build Tesla and SpaceX. Steve Jobs cared about Apple as though he were maniacal about it, like it was his true love. Who at the very top of Alphabet/Google cares about anything they do there that much? I haven't seen any evidence that there is anyone at the top of their organization that fits that.