The trouble is that stalling isn't actually against the rules of chess. If you've got 30 min for the game, you are allowed to spend your 30 min however you want. There is no rule that says you have to resign if you're in a lost position, and in any case, although some positions are very obviously lost, there will always be positions where White says "Black has obviously lost", and even be correct, but Black may not see it. It would be hard to make a truly fair judging-system. If stalling were stamped-on too ferociously, we'd have people posting "It's not fair, I was in a really difficult position, down on material, I needed a really long time to think about a critical move, I had 20 min on the clock, and I got banned after only 10 min! That's not fair!"
We can all recognise obvious stalling, but where do you draw the line between this and "desperation-waiting-thinking" where the losing player is genuinely looking at a lost position and trying to see if they've missed something, maybe some swindle, some chance to see if they can get a stalemate ending?
I'm not sure if it's possible for an AI to judge correctly yet, but for humans it's easy. Only temporarily ban stallers if it's obvious to a human that they're doing it on purpose.
I.e. I played a 10-minute rapid and I ended up having Queen and King with 6 minutes left, and opponent had only King with 6 minutes left. He spent over 5 minutes to move his King. That's obviously stalling.
Such cases that are obvious should be banned. The only issue I see is that chess.com can't have a human to check every stalling report, since there must be many. AI could punish mistakenly. So, I can't see what choices chess.com has. Maybe a human checking a staller after he's been reported over 3-5 times?
The trouble is that stalling isn't actually against the rules of chess. If you've got 30 min for the game, you are allowed to spend your 30 min however you want. There is no rule that says you have to resign if you're in a lost position, and in any case, although some positions are very obviously lost, there will always be positions where White says "Black has obviously lost", and even be correct, but Black may not see it. It would be hard to make a truly fair judging-system. If stalling were stamped-on too ferociously, we'd have people posting "It's not fair, I was in a really difficult position, down on material, I needed a really long time to think about a critical move, I had 20 min on the clock, and I got banned after only 10 min! That's not fair!"
We can all recognise obvious stalling, but where do you draw the line between this and "desperation-waiting-thinking" where the losing player is genuinely looking at a lost position and trying to see if they've missed something, maybe some swindle, some chance to see if they can get a stalemate ending?