I don’t understand. If nodes do not accept whatever the witnesses say is the true transaction history, why are the witnesses needed in the first place?
I know that it’s not possible for a witness to fake some users signature, and send these funds to themselves, but that’s not the attack we need to worry about. The attack we need to worry about is witnesses colluding to present a false history of transactions, such that the user’s funds (that the miners want) were never sent to that user in the first place, thus remaining the property of the coinbase owner. Since all coins originate as a coinbase, if witnesses go far enough back in time, all coins are theirs.
I know that it’s not possible for a witness to fake some users signature, and send these funds to themselves, but that’s not the attack we need to worry about. The attack we need to worry about is witnesses colluding to present a false history of transactions, such that the user’s funds (that the miners want) were never sent to that user in the first place, thus remaining the property of the coinbase owner. Since all coins originate as a coinbase, if witnesses go far enough back in time, all coins are theirs.