Not necessarily. Systems built on decentralized protocols can still avoid centralization. We see this with core internet protocols (DNS, BGP, TCP/IP, SMTP, etc.), and modern protocols alike (BitTorrent, XMPP, Matrix, most blockchains, etc.).
It's true that many people may gravitate towards a specific service operating on one of these protocols for whatever reason, and particularly with federated protocols, but it wouldn't be correct to say that e.g. Gmail or Cloudflare DNS are centralized in the same way that e.g. Google Ads or YouTube is.
Even when services built on decentralized protocols become popular, decentralization avoids vendor lock-in by definition, and users are free to choose any other service according to their needs. It also avoids monopolies since anyone else can build a competing service that caters to the same market.
> Your account got taken over? Need to reverse transactions? Need recourse if someone defrauded you? Don’t want to check each factoid you read? Need to ensure that users are not spreading actual terror content?
All of those are service concerns. Yes, they are easier to address when the system is centralized, but not impossible otherwise. The main reason we don't have good decentralized solutions to them is because companies have no incentive to invent them. And in the cases when they do exist, they have no incentive to use them.
I believe this is in large part due to the failing of the WWW to be decentralized from the start. Its original proposal[1] included a phase 2 of the project where "authorship becomes universal", which failed to materialize. This made it lucrative for hosting companies to fill a functional void, which gave way to tech giants, social media, and Big Tech as we know it today. I think we still would've had a need for centralized services regardless, but they would've been much less popular and powerful than they are today.