There doesn’t have to be another side to the losses. If Alameda / FTX was holding assets that depreciate in value, they would book losses along with everyone else holding the same assets.
I'm not positive this whole thing was some kind of planned conspiracy, it just seems like idiocy and fraud catching up with them. I don't think any competent fraudster would get caught in such an embarrassing way.
Btw, I find this explanation compelling - I'm not challenging it necessarily.
And those addresses are potentially pseudonymous to boot, at least if the BTC is withdrawn. If it ISN'T withdrawn, it's entirely plausible that the transactions took place off chain in the first place -- simply moving numbers around in an internal database while staying right in the same, FTX owned wallet. What you'd call in the trad fi space "holding assets in street name."
This is different from imaginary value inflating and disappearing (i.e. tokens that never had liquidity - where mark to market never made sense, etc). In that case the whole thing is a mirage.
But if $8 billion dollars went into FTX, that money does not just "disappear" from depreciation - someone else's (or many people's) purchasing power increased in relative terms proportional to the losses suffered by FTX's creditors/depositors.
Value can be created and sent back to ether. It’s not a zero sum closed system.
Let’s look at NFTs, they weren’t ever worth anything but some people thought they were, and counted them like they were, and convinced dumb people to pay for them at these prices, but it was all imaginary. The ones that never sold are just as worthless as the ones that did. The entire market collapsed, the “value” is really just gone, no one “has it”.