What will these ETF firms stand to lose should the market crash?

What does a casino lose when gamblers go broke?

The casino loses nothing.
Mathematically the house always wins.
Blackrock is the casino.

The Bitcoin ETFs are already outperforming wildest expectations.
And we haven't even gotten to 2025 yet.

The irony here is that you need to save all this energy and fear for later when the entire ecosystem is flooded with greed. I highly doubt you're going to do that and you'll end up being greedy and hyper-bullish just like everyone else even though Bitcoin is 10x higher. Because that's what literally everyone does. Including myself.