You didn't point to his numbers so that wasn't clear, but either way, Silver has beef with bsky because he isn't popular there and he likes to whine about it.
The usage numbers I've seen are down from their peak last November but have mostly stabilized at this point. The devs say they have multiple years of runway, and each time there is an exodus from twitter the numbers have a sharp increase and then decline to a stable number higher than they started.
13 months ago there were 200k daily likers and now there are 1.2 million. Yes, that is down from the highest peak directly after the election, but the 1.2 million has been fairly steady for the past ~4 months and if there's one thing you can count on it's Elon doing something stupid to piss off users and cause another user exodus. That one will cause another peak and slow decline but if it's like every other one he's caused the end result will be higher numbers for bsky than before.