I'm making more than 50% of my money from a Rails app providing a JSON API to a Vue frontend. The only HTML sent by Rails to the browser is a page with the Vue code and the initial data.

It's not the first web app with a similar architecture I worked on in the last 10 years. The only traditional app I've been working on recently is a Django app that generates HTML pages, with some JS. AI is helping not to turn that JS into a mess.