Email is similar and now most people get their e-mail from one of a few providers who exploit their data for advertising purposes. This is exactly the problem we wish to distance ourselves from in regard to centralized social services such as Facebook, Twitter, Youtube, etc.
If you're not the customer, you become the product.
Mastodon and the Fediverse made decentralized software that people want to use - but they didn't come up with a way to make it sustainable. Web3 has a model of financial sustainability, but they've yet to come up with any other decentralized software that lots of people want to use. These two communities focused on decentralization should really collaborate more.