Wide rollouts have come every ~6 weeks, like clockwork, for a good 9 months now. I would expect this one will likely go to most of the fleet if they’re keeping with that schedule.
As a software developer, I would bet dollars to donuts that there isn't a hard six (or eight) week "schedule" for fleet-wide FW update rollouts.
Correlation is not causation.
I think when they have an update that's has some significant new features to be released, or critical bug fixes, and has been test-rolled out to a small number of cars, they do a fleet-wide release "when it's ready."
Just because it looks like a scheduled release program doesn't mean it is. For instance, the HO HO HO easter egg was hastily rolled out one day before Christmas. Luckily it didn't introduce any regression bugs (well, that we know of so far -- ha ha )