An exact example of the kind of thing I'd like to get rid of.
The UK PC vendor Elonex had the first ever webmail system I saw, called HTMail. It was impressive but it was a private in-house tool to give remote workers email access without needing their own machine with an email client. Wrong sales model.
It the was followed by the indie HoTMaiL, based on NetBSD servers I think, which had the right model: a free public standalone service, paid for with ads. Of course MS bought it and ruined it.
Webmail doesn't need Javascript and worked with pre-JS browsers and servers.
> For example, a platform-independent chat app.
Good. Let's eliminate them, too. They are bloated slow things that allow companies to hijack their own commercial clients' data.
Stick to standard protocols, extend them if necessary -- XMPP 2, Matrix, whatever -- and document and publish the protocols. Make it possible for 3rd party client apps to connect. Pidgin was great and it takes about 1% of the RAM of a bare handful of these crappy Electron efforts like Slack.
What you are citing as reasons to keep it are the reasons I want to see it dead.