a clock in the context of a distributed system is a method of providing a partial ordering (a happened before b). most blockchain implementations use a merkle tree that uses predecessor transactions as inputs to the output as the clock

regardless, blockchains as implemented in certificate transparency and bitcoin aren't actually consensus systems, they are just (highly accurate) approximations

Both of the points you make are true but how are they relevant here?

We are talking about clocks that tell time in the quoted quote (time is ordering of events by definiton) & consensus in bitcoin is final(accurate) enough an practical approximation as much as a centralised system as described in OP is. Either I am misunderstanding or this is your dislike for bitcoin.