Decentralised services always come out years later centralised services are launched and their only raison d'etre is not having the rules of those services.
Yeah, I still remember when the web was only a product of Web Inc., and how long it took for independent webserver implementations to take off.
Or, before then, do you still remember when email was this walled garden where everyone had an account with Electronic Messaging Solutions Inc.? It took decades until sendmail, exim, qmail, postfix, and so on came along, largely thanks to Google's help in breaking open the former monopoly, and people could finally host their own email servers!
Ah, yeah, true, I still remember the days when the walled garden or IRC was the only option around before XMPP was invented.
Are you sure you aren't just saying "those decentralized services that happen to be built as replacements for centralized services come out later than what they intend to replace"? Well, yeah, of course they do. While those that happen to be invented decentralized first come out decentralized first. Also, I think email still is a decentralized service of today? And yet, gmail seems to be going strong in centralizing email, doesn't it?!
Or, before then, do you still remember when email was this walled garden where everyone had an account with Electronic Messaging Solutions Inc.? It took decades until sendmail, exim, qmail, postfix, and so on came along, largely thanks to Google's help in breaking open the former monopoly, and people could finally host their own email servers!