> people move to the next thing, thanks to the decentralization

This does not quite follow. Care to explain more? What I observe in practice is that people move from one centralized service to the next centralized service (e.g., X->BlueSky) but rarely from centralized to decentralized.

Most services aren't decentralized, but the Internet itself is decentralized, which allows to set up these independent services that can compete with each other.