He still has to be making money.
Why else would the site still be running?
The site may still be online, but only because operator has left it.
He cannot be making any money if the deposits have stopped

I doubt the deposits have stopped.
There would be no point and a greater paper trail to leave a site up that is not generating income especially a site that is ran by a thief.
No need to doubt it, take a look here :
https://blockchain.info/address/19mcjofGwKxGwhaZwDwPjdWd1KrFCZgoJJLast deposit 2016-04-30 19:07:39
Paper trail? you mean fake credentials left with a hosting company that is hidden behind cloudflare?
The site will be left until the paid for hosting and site certificate runs out.
Wouldn't be the first time the deposit address was changed, I'd have to make a deposit to know for sure it is going somewhere else but am not about to do that. Trade being completely frozen for such a long period really looks like abandonment as you said, the little bit I had left in there is considered gone but I still log in from time to time to see it has grown a tiny bit into a slightly bigger small amount I will never be able to withdraw.
I doubt there's much of an easy to follow trail although people do get sloppy, if someone lost enough and had the resources to really dig into it I suspect they would have made progress by now so agree that it isn't bloody likely.
I figured out what happened to Marcello though, looks like he's giving new video interviews about his new job!
https://www.youtube.com/watch?v=RC3NH1a8uEU