Even if satoshi stayed what do you think he had left to offer to bitcoin? He dreamt of a decentralized currency that everyone can use and its users would decide about its future, if he stayed and took a leading role in the development wouldn't you agree that he would see his dream crashing down? Every single of his move would affect BTC as people would see him as their leader, their creator and possibly for some he would be the reason they ran into money.
You would think the man can fly, LOL, the way folks talk about him.
Satoshi is irrelevant at this point. There, I said it. Given how democratic this thing is, its akin to the Founding Fathers writing the framers. Once they wrote it, it became a living document, subject to "version upgrades" and "new features". Bitcoin is like this, a living thing. anyone can add to it, but the community has to agree on those changes.
He had to also know he would not be able to touch his coins without burning the world down; if those coins start moving it will be a race between you and I to the exchanges
What could he contribute at this point? despite making his intentions plain, we have suffered with a gimped product due to the politics of this. I dont think folks would listen, to be honest. which is probably the reason hes left it alone, if hes still alive. its kind of been corrupted.