Lightning Network's RSMC: what happens if there's no revocation transaction?
My assumption was wrong: in a RSMC (Relative Sequence Maturity Contract), a Revocable Transaction refers to the transaction whose output can be spent after a specific amount of time (eg: 1000 blocks) by the counterparty, not the original party.

The counterparty won’t get all the funds in that channel, but whatever was their balance before. After 1,000 blocks, if the original party doesn’t notice the malicious activity, the counterparty is able to spend (presumably) more than they should (as the counterparty published an old Commitment Transaction, it means that they try to reverse the payment for whatever service or product the parties).

This is the reason why users may want to monitor the blockchain for old Commitment Transactions, as a counterparty caught broadcasting an old one will lose all their money when a BRT (Breach Remedy Transaction) is broadcast. The BRT’s private key might be delegated to a third party “watch tower”, since they can't do any harm.