it is less of an oversimplification than 'nothing like what existed either before or after'

Clipping the quote like that completely changes the meaning of what I said. I didn't say that.

But I stand by what I actually said: Smalltalk's OOP is indeed very novel, even for today, especially compared to C++/Java, but it's also very different from Simula, especially the early Smalltalk versions.

It's not without lineage (Ruby and IO) or peers (Erlang), but it's still an incredibly different flavor of OOP than Simula. This is not a slight, this is a compliment to Alan Kay. But to compare it to C++ is to miss the mark. C++ is from a different branch of OOP.