With lots of things being developed through web technologies, and many things being web-based so that it is cross-platform, will operating systems still be relevant?

We can differ philosophically by using Debian or Arch or Windows or Mac, but if nowadays applications are web-based or developed through something like Electron such that it can run on practically all modern operating systems. what is the relevance of operating systems galore?

Don’t get me wrong I love FOSS and Linux and stuff, but it seems that the paradigm right now is creating web applications, with many things being web-based.

Am I off, or is this something you also think about?

P.S. I’m a total noob when it comes to IT, so the question might be weirdly phrased.