There is a very basic argument, not against decentralization per se but about its real power: even imagining a future where you can decentralized social networks like Facebook, at the end people interacts with the service through an application and this application dictates what the user sees beyond the protocol.

For example, OpenBazaar is a decentralized marketplace but if people search for products in the GoogleBazaar site, GoogleBazaar can sort or hide the items as they wish not matter how perfect the decentralization protocol is.