Centralized platforms grew this large because it served the capitalists behind it. The growth didn't happen because it was healthy for the communities, but healthy for billionaires' bank accounts. Smaller communities that allow individuals to connect to the people and topics that interest them are the solution. It won't lead to the next class of billionaires, but it will lead to a healthier Internet.
https://www.theverge.com/2023/7/3/23782607/social-web-public-apps-end-reddit-twitter-mastodon