Consistency Locks -> Clocks
The idea of locks being the only mechanism for isolation to guarantee the consistency are long gone. When these ideas were being debated, the data sets were very small, compared to today and distributed meant another computer in the same building somewhere (mostly).
The state of the art in transaction coordination and consistency mechanisms has gone beyond distributed locking because it just doesn't scale. It has shifted in favor of algorithms that use time based coordination in distributed databases.