I think the reason my friends did not join Bluesky despite me inviting them is that it just isn't as good of a product as Twitter. You can't post videos or DM.
I am not a tech executive and have no idea about corporate strategy, but it seems like Bluesky should focus less on technical differentiators and more on building killer features that have mass appeal and a community that people want to join.
IMHO this milestone, while cool, means absolutely nothing to people outside of the hacker news crowd.
I'm rooting for Bluesky, but it seems to me it will die without a critical mass of users.
Again, I'm kinda dumb, so this may all be wrong.