Humans hate friction. If Threads can offer fediverse search, quote-posting (they already do), easy discoverability of friends (got this part mostly done), multiple timelines (a la Bluesky), ditch the weird Masto reply vibe, etc., people will use it over other apps/instances. And then make it easier to stay than to switch to something else. It'll be interesting to see if FB plays the long game and doesn’t overload Threads with ads too quickly (major friction for many).