These are incredibly well funded an knowledgeable institutions and individuals with access to privileged information...they can keep it up forever, while they profit from other trades in the same exact stock. They also borrow stocks from other partners that will give them preferential treatment as far as fees and payment terms, if not for free just to keep their shared interests afloat. If these highly shorted stocks didn't already close, they've made a shit-ton of money already from all the volatility they have seen, and have enough money to "cover". While all these naive fanatical retail investors have been holding on to unrealised losses for years, they have masterfully moved their capital with swings in market momentum and extracted billions from the markets. Yes they do manipulate markets, yes it's rather legal, and yes they are highly trained an efficient at doing so, with access to an unlimited pool of human and money capital... thinking that you are going to win through some miracle short squeeze is past delusional, and it's sad. History will tell.