The browser-as-a-platform is based on a lousy programming language addressing a lousy object model and using a lousy stylesheet language for visuals. Each of those could and should be replaced by something better. HTML? Not perfect, but plenty good enough.
Not only is HTML finished; Even if we wanted to improve it, there are no obvious candidates to do the work. The W3C has repeatedly walked down blind HTML alleys. The WhatWG model was never remotely sustainable.
Je me demande parfois si l’arrivée des composants web n’est pas un moyen de ne plus avoir à revivre le grand n’importe quoi qu’a été HTML 5/Living Standard. La main invisible du Web appliquera son darwinisme habituel.