I don’t really care much about what Kay says. His view of OO isn’t what caught on. C++ as a descendant of Simula, which is considered the first object-oriented programming language, certainly supports OO. (C++ is really a multi-paradigm language.)
Object-based means OO without inheritance or subtyping.
Implying that the inventors of Simula had a time machine?
I am inclined to think the more logical explanation is that they didn't actually take OO back in time and that Simula isn't an OO language at all (perhaps confused by the first OO language being created with Simula?), but admittedly I'm rooting for the time machine! Look forward to you telling us more about it.
Object-based means OO without inheritance or subtyping.