The market expects the bank going under to impact Roku by that much expected value. That's very different than saying the market expects a certain percentage of money to be returned in the end and it's not clear why this is supposed to give even a ballpark estimate of the expected recoup. After all the share price has way more to it than what the current assets come to.

It's also very likely the market changes its mind shortly, especially if Roku lays out the plan and expected impact to operations in more detail.