I still believe the highest possible rating is ~3600. Stockfish's rating is lowered by the fact it wasn't allowed to use its opening database.
But AZ didn't really either (it used its learned book). My guess is the results probably wouldn't be a lot different, even with the opening book set for the opponent (Stockfish in this instance). Better hardware on the Stockfish side would likely help some more (to offset the benefit of the Tensor Processing Units of AZ/DeepMind).
I agree on the top rating, which would be the max rating it could get by beating the highest rated human players 99% of the time.
Wow, I've been wanting to see this match since Alpha Go beat Lee Sedol, Stockfish is like a Ferrari but AlphaZero is like an airplane....Doing something fundamentally different. Think of the wright brothers, They couldn't go faster than a modern day Ferrari, but with a long enough time-line Jets are the fastest things we got (outside of space travel). I don't think anyone can imagine what AlphaZero could do if it played chess for weeks or even months....5,000 Elo? 10,000? 15,000? Chess has been solved? Period.
That really doesn't make any sense. Rating is based on the probability of winning over other opponents. Unless it gets strong enough to win almost all games, then it could be 677 point higher rated than it's opposition.
If it is true that chess is most likely a draw, which the results seem to imply is still likely, then the ratings won't ever get that high.