Yep; the only current advantage that blockchains have over current CT logs is trustable global transactions. This is a pretty powerful advantage, but the proba

Yep; the only current advantage that blockchains have over current CT logs is trustable global transactions. This is a pretty powerful advantage, but the probabilistic certainty can be shifted from confirmation height to fraction of log inclusion and cost-of-revocation, e.g. transactions can be proposed in one or two logs and then confirmed by a supermajority of acceptable logs (to the transaction) once the ordering of potentially conflicting transactions is established within at least one log. E.g. double-spends are prevented by announcing a transaction with a TTL that is included in at least one log, such that no conflicting transaction appears within any other log before the TTL expires, at which point most/all logs accept the permanent transaction. Inclusion in a supermajority of logs provides the probabilistic likelihood of the transaction being durable (e.g. irreversible), and individual CT logs become invalid if they sign a later conflicting transaction. Economic incentives could be as simple as charging customers for inclusion of their transaction in the log with escrow to refund all customers if the CT log becomes invalid. This can be implemented as its own CT-log transaction because logs have an incentive to cooperate with each other on signing off on the successful completion of a valid CT log (after a year or whatever) so they all keep getting paid.