The internet is centralized because we have asked for it.
What is the purpose of having multiple social media sites?

Will you go into "facebook", then "y" and then "z" to find out what have your friends and family posted/shared?
Hell no, people want one site where they can consult everything/the most related to it. (One of the reasons of why Instagram is destroying Snapchat).

I think that it is better this way, my only concern is that the shareholders of those platforms are getting rich, when the users and content creators of those platforms should be the ones making money, blockchain will definetely democratize this.