I’d fear instead that centralisation is pretty sticky without some massive failure and wouldn’t expect much movement in the proportion of users on lemmy.world.
It happened in August during the long DDoS attacks on LW.
I guess here it's less prevalent because the site is still accessible, and most of the users don't really follow closely the Lemmy versions.
It probably didn't show up in the first place it only has 66 subscribers, and probably none on SJW.
About your second point, you indeed have to promote your community, using !newcommunities@lemmy.world, or related communities. This works quite well usually.
I will add that in your case, people knew about your community as you posted in other communities, but as discussed then, people seemed happy with the existing Reddit-focused communities.
But wouldn’t it be great if the knitting community (for example) on beehaw.org, lemmy.ml, lemmy.world and feddit.de would be merged for me into one entity for a better browsing experience?
Why wouldn't they merge on one instance? Seems easier, and can be done today compared to having to ask the developers to implement a complex feature.
I'm talking about desktop experience, but sure...?