Think about things from the point of view of someone who has never used Reddit or the fediverse, but you've heard about them both from recent news articles and want to see what they are about.
Reddit:- You Google Reddit and your first result is Reddit.com. You click the link and are presented with the front page. You from scroll from a few hours and end up signing up and staying.
Lemmy:- You Google Lemmy and your first result is a wiki article for Lemmy Kilmister... Your second result might be join-lemmy.org, which you're smart enough to realise it's probably more likely what the news is about.
You click join-lemmy.org and are presented with a page of information about the fediverse, links to set up a server and pictures of code...
There is very little chance you're going to investigate further.
If we want the fediverse to replace Reddit then either
A) Lemmy needs to improve its initial impression and Search engine optimization
B) We should be promoting a different platform with a better initial first impression.
I'd recommend kbin personally as it gives the same sort of experience as Reddit from the initial interaction.
The thing that helps Kbin the most is that it is, by far, the easiest to understand. Googling "Lemmy fediverse" gives a bunch of various links to other Lemmy instances, which are presented in a way as if they are separated from one another. Kbin appears as one site, one location for content aggregation. Although that "goes against the idea" of decentralization, most users are currently looking for their "one home to replace their old one home". The more users flock to one area and learn how it works, the more things will begin to take their proper shape, so to speak.
A feature we'll definitely want to have with kbin in the future is the ability to migrate accounts to other instances. That would mean that even though we're centralizing on kbin.social right now, people could move to other instances and spread the load across the fediverse without losing their history
I'm still learning the ins and outs of this place and the others, but part of me thought that was the feature of being federated. User accounts could seamlessly transfer from one instance to another.
Looking further into it, it looks like that feature exists for content, but not so much for accounts.
You can access content from an account anywhere, but not migrate the account.
I think it exists in Mastodon, it just hasn't been worked on yet for Kbin / lemmy.