So they probably could get even more users, but I'm guessing it's already sufficiently crazy for the team right now
With which backend? Scaling from 200k users to possibly hundreds of millions that quickly?
Besides, 'limited' account creation to form communities is a pretty well-established scaling strategy. They have scaled from 0 users to 200k users in 5 months - Facebook originally took a year to scale to 1m users so it's not unrealistic that Bsky are growing/scaling at approx the same pace at this stage in the curve. Worth noting that Facebook also just couldn't have handled scaling to 1 billion users on Y1, and that required years of engineering effort (and lots of money/resources).
Considering they can only have limited users at their current stage, invites to form close communities is a strategy to ensure that a social graph is created early. Having 20k users that all have a few friends with accounts is more important than having 20k users where nobody knows each other.
Remember Facebook also originally scaled campus by campus - which was a process that let it 'scale' in a way that encourages social graph creation (i.e. 10k signups in 1 university is probably WAY better for a social network than 10k signups in 100 universities).
Has anyone else created a decentralised social network at this scale? Arguably matrix but they also grew slower, potentially have a simpler product, and had scaling challenges along the way.
Remember scaling doesn’t just mean technical for a social network - it also means support and moderation.