People, at large, do not choose social networks on their technical or purported societal merits.
People choose social networks because of interesting people on them (ideally helped by ease of finding interesting people, ease of use and a lack of technical jargon).
Thus, if you want e.g. Mastodon (and it's technical and/or societal merits) to be successful against Big Social you need to compete on making it easy to find people and ease of use the software; it's really that simple.