IMHO these are fundamentally different concepts. Popular social media is made popular by pushing curated 'engaging' content, rather than organic content, to monetize gullible users. It has become an entertainment venue, giving their audience a steady stream of what they want them to see, even if by force. Popular "Social Media" has rapidly devolved into a real-life MST3K. Users feel betrayed that the sites no longer feel like the social experience/experiment they wanted.... but are users really wanting to leave, or just switch to voice outrage?

Alternatively, the fediverse doesn't appeal to those wanting force fed entertainment, or seeking viral fame amongst family/friends, and outraged users will complain it doesn't function like so-and-so site, or work 'their way'. It is more technical and takes more proactive actions to engage with others, which is a positive thing.

Users think they can switch from Coke to Pepsi, but the fediverse is more of a mixed drink with some extra bourbon.

Could it / should it replace popular social media? Probably not, unless more mindsets change over what a social media experience should be... but it can fill a growing gap as this happens (which will in-turn improve features & development).