But where would a unified Web client run in the first place? It would have to be installed on a Web server and, from there, access the Web servers of the various different server apps which would still be entirely different and independent installations.

For a Web client with no actual server backend, the same would go as for a mobile app: It would have to cover pretty much all features of everything. If uniting Lemmy and Mastodon in one UI seems tricky already, try adding Hubzilla and (streams) to the mix.

If you’re actually looking for a unified Web server and client, i.e. one Fediverse project that literally covers everything the Fediverse can do with one login on one server and one identity: This won’t happen.

This would be way too much for one Fediverse project to tackle. You’d basically have to start with (streams), add back all functionality that has been removed since the first fork from Hubzilla (and that’s a whole lot), make all kinds of non-nomadic protocols compatible with nomadic identity via Nomad and ActivityPub, and then gradually add all kinds of features from all over the place, from PeerTube to Funkwhale, from PieFed to Owncast, from Mobilizon to BookWyrm. And you’d have to soft-fork everything and keep them in-sync with their respective upstreams.

The outcome would be too complex for most. People would have to deal with their account/their login not being their identity because their identity is containerised in a channel. They would have to wrap their minds around nomadic identity. They would have to deal with fine-grained permissions settings. They would have a post editor that’s every bit as powerful as those on big blogging platforms when all they want to do is tweet and retweet and occasionally watch a video. And they would have tons of features on top.

The whole thing would be an utter nightmare for its developers as well, seeing as they’d constantly have to track over 100 Fediverse projects and implement any upgrades which they’ve rolled out.