Okay toss an S in front of FTP and we'll consider that fixed.

DNS isn't centralized. It's decentralized by design. Anyone can run a DNS server. Registrars maybe? But those are a dime a dozen too.

SMTP is only medium-centralized because it's a pain in the ass to run a mail server now due to spam. Anyone can still run a mail server and put in the work to make it not get blacklisted.

I don't get how TLS is centralized since we have dozens of entities that can issues certificates.