I also think GCloud is very unique in that all of the capex that Google spends on it comes back to benefit Google. All of their product offerings need servers and world class networks behind them. So even if GCloud remains a solid third/fourth place in the cloud race, I doubt we'll see them go anywhere just because Google itself is probably using it internally to some degree.
I mostly worry about the scope of investment from management. I want to see way more products out of them. More managed databases, a better managed NoSQL database than Firestore, lower prices, more enterprise focused things like automated security auditing, better support. We're just not getting it; they're so focused on shiny trivialities like Firebase and Stackdriver while missing the basics.