IMO it doesn't need to replace Reddit for everyone or grow to be a direct competitor. As long as there are enough users to keep communities active and discussions going, it's a nice alternative for people who want to get away from Reddit or other social media sites. I like that threads are active for longer than a few hours before dropping off, and since posts are slower I don't find myself mindlessly scrolling. Lemmy feels more like a mid 2000s forum but with better usability.
Lemmy doesn't need to be #1 in popularity. I'd prefer it to split and maintain a higher level of quality, even if it's smaller as a result. Even if Meta can grab data either way, it should be disconnected on principle.