Do not forget the emotions at play. Financially it might not make sense, but the feeling to be part of the team that "sticks it up to the man" might play a role in the decision to join, even this late.
Sooner or later it will pop, it's not like the GME business suddenly got 50x more valuable (and it's not looking to get, any time soon). So the last suckers will be left with an expensive paper that pays little to no dividend, or they can try to sell it to a market where no one wants it.
Try to train a HFT algorithm to account for this.