You don't just get asked to resign, you get made an adviser for awhile and still paid! Tony will be an adviser for a set period of time and still collect a bunch of money, which will help him save face and probably prevent him from working for other tech companies for a specific period of time. My guess is that he will be an adviser for 1-2 years.
My guess is that this is a way for the non-compete agreement to be enforceable until enough things get fixed so Tony's knowledge about what is broken no longer matters.
Depending on the nature of the separation, Tony may never be at Google again. It really depends on if they left on semi-good terms or not. Tony probably won't be allowed the Nest team, but Larry may still value his opinions on where the products should go, even if Larry thinks that Tony is a poor manager.
The press release conveniently leaves out the Office of Inspector General's investigation of Butch, his wife and his step-son regarding a marijuana investment promising $44 million in revenue. Nor the fraud, extortion and numerous scams by his step-son.
"No doubt"? Really? He's been there 2.5 years which is longer than most founders stay on after acquisition. It's certainly possible he was fired. Maybe even likely. But I certainly have some doubt.
He's an "advisor". He has neither moved on to a more prestigious role in Google/Alphabet, nor has he started a new company (that he's announcing publicly), nor has he moved to a prestigious position elsewhere.
Curious why he would need to move to a more prestigious position? Most people realize by their 30s that prestige is a sucker's game; it's a way of inducing people to do things that aren't much fun and they wouldn't really want to do on their own, by lauding them with accolades from people they don't really care about.