That’s a little different than what they’re talking about here, I think. Admittedly, my understanding of these things is only as good as one could expect from a layman with a passing interest in these subjects. Still, one might suppose that this splitting of universes into every possibility extends right back to the big bang, with every possible universe having come into existence at that time. That of course assumes that there is any truth in the many-worlds interpretation, and that the current belief in the universe having a starting point (the big bang). I’m not sure any of that is true, although the big bang at least does seem to be the explanation that best fits the evidence that we have at this time.