Most people are severely unfamiliar with the concept and curating it to your tastes tends to be a barrier of entry

See Reflections: The ecosystem is moving (2016) by Moxie Marlinspike the founder of Signal (privacy oriented secure messaging app).

The gist of it is that decentralised systems are more difficult to evolve by their very nature, therefore we need centralised but public† services to keep up with the pace of centralised and private ones. Another emphasis is on the word "services" as software alone is often not sufficient without some server component, centralised (e.g. Signal) or federated (e.g. Lemmy).

† Public as in the commons: owned and controlled by non-profits for the benefit of public.