You may not like my answer but here goes: Time will tell.
Those who have jumped ship indefinitely will build a community here in the Fediverse. Those who miss Reddit too much will return there and use the official app.
By staying you are building something new. It may not be Reddit, and it may never be Reddit. But there are still millions of users who are here to stay and will become a community.
I hope it will not become a "they" vs "us" thing. Both platforms can exist peacefully, the same way Facebook and Twitter coexist.
Perhaps a difference in content style or format will appear in time, which will make people choose one platform over the other. But that's not bad. Competition is healthy.
I'm staying, and I'm curious to see where Lemmy is going. All I can do is contribute to making it a place I want to hang out in.