Throughout much of the book, I was reading it with the possibility in mind that the two futures were not in alternate continua, but that one might be a post-singularity simulation running inside the second. This seems to not be the case, although I wasn't sure until an offhand reference in the author's end note.

I wonder why Gibson didn't embrace that ambiguity. Maybe because it would weaken the characters -- at least I often find books that go that direction to have characters who are too cold and inhuman underneath, while here the main two characters are very warmly human in their different ways. Maybe he just generally wanted to avoid the Singularity rabbit-hole (can't blame him).

The mysterious Chinese server -- that neither side seemed to investigate or attack the other side's connection with in any way, seems like the biggest plot oversight in retrospect.

Anyway, very poetical read, in a sawed off shotgun at McD's kind of way.