Giving them time is exactly my problem. That's exactly embrace extend extinguish works.

They start by embracing it. "We created our own fediverse instance isn't this a cool thing, come on over to our server you can see other servers and leave anytime."

Then they extend it. "We added a colorful widget, only available on threads!"

Then when they feel they've got enough of the core users, they extinguish it. "If you want to see threads content you need a Facebook account, sorry just to meant be features to stay federated."

Look at what Google did to RCS for a real world example.