Still I am very happy to use every day the technology designed in early 70s by Ken Thompson and colleagues, so far in that specific field many tried to invent something more "modern" and "better" and failed, with an exception of a certain Finnish clone of that tech, also started in 80s by the way.
Speaking of which, if you try an actual System V in an emulator, or look at C code in K&R style, certain progress, as in "much more actually usable", can be noticed.
While persisting key architectural ideas certainly has benefits, so does evolving their implementations.
Yes I agree that implementations must evolve. Still, there are cases where old architectures are just brilliant.
Having said that, I need to add, I am not an expert to say MVCC is good enough to be considered equally good like other write-concurrency mechanism in SQL databases. My example was given to just have a caution when judging, especially that the original counterexample had mentioned notoriously bad architectures (hello, MySQL...)
So, newer not always means better, just saying