If Satoshi were watching and cared, all he'd (she'd) have to do is send an appropriately-signed text via Tor or whatever saying Craig is a liar. Coming forward in any substantial sense would be unnecessary.

That Craig is proceeding with this big hoax regardless means either that A) he knows who Satoshi is, and knows that Satoshi is cooperating/dead/apathetic/etc, or B) he's looking for sufficiently short-term gain that there's low enough risk that Satoshi would intervene in time.

Watching, cared, and still had access to those keys.

I'd trust the brilliant mind behind Bitcoin to hold onto some backups of keys worth half a billion dollars. Since you never know, such a a thing could come in handy someday.

I wouldn't, you can be a genuis and still be lazy about backing up and rotating your super private personal key.

Alternativly, he could be altruistic and deleted the Statoshi key to protect against manipulation, including from his future self.

There were many years where the keys guarded bitcoins worth approximately zero.

And shit happens, even to geniuses sometimes.