I think it is some mixture of luck and working primarily on distributed systems where the "default" is to in principle avoid locks or hide them behind something

I think it is some mixture of luck and working primarily on distributed systems where the "default" is to in principle avoid locks or hide them behind something like a transaction, where optimistic locking is what is happening under the hood. I think this is the "right" level of locking for "mortals", though complex transactions can quickly become hard to understand as well. Irrespective, thank you for the link and comment, I haven't interfaced with many of the scenarios you shared!