It's objectively awful... But when you step back a tiny bit, that doesn't matter. What matters is the inter-organizational community it achieved. If these organizations wanted to continue, they could come up with a negotiation technique like in http - both ends can use whatever fancy thing they both support, but fall back unto riding dinosaurs if that's the only thing that works.
I often swing between longing for a federated protocol that can be managed by technical people and used by everyone, like XMPP, and something more P2P to reduce centralization and allow everyone to instantly "open an account" with no need for technical skills, but that still needs some kind of relays for asynchronous communication, like ssb. None are technically perfect (although I really like the simplicity and extensibility of XMPP) but in the end what matters is not that: it's about how the protocols are used, how they allow all of us to communicate, how they give more power to those who aren't already using the internet to exchange information. And that is not a technical problem
They are "great" from the perspective that the non-tech-savvy user somehow can get into using these. This did not work for XMPP (they need to learn that they need to pick a provider and a client; then they need to deal with entering the credentials into the client; then they need to solve problems like history synchronization and access from multiple devices; and finally voice/video/filesharing over XMPP is a disaster).
I agree onboarding can be a hurdle (for any decentralized network). These days many XMPP clients support invitations which make the process much easier (see https://blog.prosody.im/great-invitations/ ).
This easy onboarding is a fundamental part of Snikket - allowing you to bring groups of people onto XMPP by just sharing a link with them.
