Good points regarding HTTP, but XMPP is an excellent example on how decentralisation can be detrimental to the user experience. A large percentage of XMPP user

Good points regarding HTTP, but XMPP is an excellent example on how decentralisation can be detrimental to the user experience. A large percentage of XMPP users are using a lowest-common-denominator client like Pidgin that supports only a small fraction of XEPs. The excellent Conversations client for Android is only on par with Signal if you use it to talk to other Conversations users using a modern server like Prosody. Good luck with simple tasks like sending a picture, otherwise :( The only truly successful decentralized application protocol besides HTTP is SMTP, and even that is becoming increasingly centralized, with vendors like Google extending it with extra features on their own platform. This kind of "protocol ossification" of decentralized protocols is unfortunate, and can be seen even in core internet protocols. Any attempt to improve upon TCP like Multipath TCP has faced huge issues with overly restrictive middleboxes and very slow propagation of new kernels, leading to userspace TCP reimplementations like gQUIC, now standardized as HTTP/3.0.