One of us is misunderstanding the “attack all DCs at once” issue and it addresses multiple of your points either way.

When I say attack multiple drive chains, I’m not talking about attacking them within the drivechain rules, I’m talking about attacking the hash rate escrow. In that since they don’t care what the rules of the DC are. They are simply replacing the “valid” DC peg out with an invalid one, and ACKing it instead. But because there are blind merge mined, what stopping them from doing this on every side chain at once? They can apply their hash power to all of the escrow transactions simultaneously, and send the DC ecosystem into a scramble to do full validation of everything to know the “honest” from the “malicious” peg out. If they don’t, then there’s no way to know the truth. In other words, just like some of the coin pool proposals require a mass exit of all transactions to L1 to enforce security in the case of an attacker, then it seems that this trade off for DCs is to require a mass validation of the whole ecosystem by miners in order to ACK for the honest transaction.

Which means to me, that in many ways it has the same centralization concerns as bigger blocks. While a negative externality is that it has the potential to change the mining profitability dynamic on L1. And we don’t necessarily know how either.

I just think serious skepticism is warranted. I wish we could see it active with real value behind it and just test a large scale attack, like 70% of the hash power, to see how it plays out. Just having some testnet DCs isn’t giving us much there. I want to see the failure mode beaten to death.