Right now the user count Lemmys is comparatively tiny when held up against reddit - but the user count isn't the thing that makes a social media site, it's the engagement
So even if you're used to lurking, try to get a little more active! Post memes, vote on posts, talk in the comments, whatever!
If people come here and see activity, content, and discussions, they're more likely to stay and contribute their own - if they come and see a ghost town, they'll just go back to reddit
Same problem Mastodon had, the content consumers joined, but the content creators didn't, so there was nothing on the platform to engage with.
And let's be real, Lemmy is going to face the same fate when inevitably the Reddit protest ends in a couple days and everyone goes back to Reddit. Reddit is going to survive.
People will probably start using reddit again, but it doesn't mean everyone is going to abandon Mastodon or Lemmy. Some certainly, but many will just use them both. I have all three apps installed now and intend to keep using them all.
I think a massive difference between Twitter and Reddit is that Reddit isn't very user-centric. It's not about building a "personal brand" or amassing individual followings.
That's why I believe a decentralized Reddit clone (akin to Lemmy) has a much larger chance of thriving.