As long as algoritmically driven centralized content pipelines remain popular, the Fediverse in general will not capture the mainstream.
Say what you will about Lemmy and Mastadon et al being “straightforward and easy to use”. I’m sure it is for you. But there’s a reason most mainstream platforms treat their users like absolute cretins: the majority of mainstream users are, and they both enjoy and expect being coddled and catered to by the platform.
The very notion of Lemmy being sharded into “instances” and what that means is so antithetical to the common preconceived notion of what a social media platform is to most people. “Oh, it’s not just all here in one place?” And yeah, federation greases the wheels a lot so no one even has to think about instances… until a community you like is suddenly rendered inaccessible via defederation.
Also, content discovery on the Fediverse is admittedly kind of ass. Only those who both know what they want going in and where to look for what they want really get anything out of it. Most centralized social media platforms are relentless content recommendation engines because people don’t actuslly know what they want until they’ve had it brought to them. An algorithm that at least attempts to adapt to what you want to see more of is a key part of that. Lemmy does not have this (nor should it).
All that said, the fact that Fediverse platforms like Lemmy filter “common people” in these ways is, from what I can tell from here and elsewhere, a feature, not a bug. By being here at all, you prove a kind of baseline competency and a willingness to put in effort to learn the system that sets you at the forefront of most social media users. Most of us like it that way and are happy to keep growth of the community stunted in exchange for it.
Of course, all of the major platforms were in those shoes at one point. Will the Fediverse be the ship everyone leaps to next when the current platforms become so enshittified that even the main stream hates it? Maybe. But wherever the main stream goes, enshittification inevitably follows. The mainstream success of the Fediverse will synonomously be the death of the Fediverse as we know it. I for one would like some more time to hang out here before then.