That's not necessarily true, economic transactions aren't necessarily zero-sum. I would assume for most of the assets being sold to the Fed, the banks need liquid cash more than they need the asset and so would be willing to take a haircut.
>The only way this ends is either a depression the scales of which we've never seen in history before[...], or a hyperinflationary collapse of the U.S. dollar
Why specifically do you think this will happen now when it didn't happen post 2008? Sure the scale so far seems bigger, but also the scale of the hit the "real" economy is taking is much bigger. And, in March, when some of these asset purchases had already started, CPI declined by 0.4%.