Someone is paying up.
Here’s the part that makes no sense to me: why can’t Robinhood use customer funds for their deposit? Imagine a degenerate case: all but one client make no trades at all. One client has $100k deposited and buys $100k worth of GME. Prior to settlement, GME drops by 50%. That client is (effectively) out the entire $100k, and they are owed $50k worth of GME. Robinhood needs to post somewhere between $50k and $100k of collateral to the clearinghouse.
This all seems entirely reasonable with one giant of exception: apparently Robinhood may not draw on the client’s deposit for this. Never mind that, at settlement, the client will be debited the entire $100k. Somehow Robinhood is expected to temporarily come up with an additional $50k-$100k for a two day period. This seems bizarre to me.
On the other hand, if they go bankrupt, then their assets are used to compensate (as much as possible) to everyone they owe in cash - not (as previously expected) in that stock. So the expected huge future purchase of the shorted stocks never happens, and all the WSB people who are holding the stock get to keep it or sell it to each other, as all that compensation money does not flow to the market for GME stocks as it would be if the shorts were actually covered. The brokers would be liable, and they might have insurance that might be liable, but all that liability would be cash-denominated and (as far as I understand - if I'm mistaken, please correct me) would not obligate anyone to buy any GME stocks.
The second big difference is in the timing. The current price is driven by short-term expectations, a hope that somebody is going to (or would be forced to) buy large quantities of that stock soon. If one of the shorting hedge funds goes bankrupt, then any settlement for that will take many months, and that money won't influence the market for that time.
The remaining assets the firm has would be liquidated, those would be used to pay off debts, including those owed to the brokerage. I'm not 100% sure how this works, like, if the estate would purchase as many shares owed as possible, or if they would settle in cash with the brokerage, or what. But, regardless, that wouldn't happen until long after the epicenter of this black swan event.