This isn't about JS frameworks, it's about rendering data on page load. Whether the server renders the data into HTML it responds with or there's some XHR requ

This isn't about JS frameworks, it's about rendering data on page load. Whether the server renders the data into HTML it responds with or there's some XHR request made by a client library (including VanillaJS) or framework, you're always incurring some cost. But data-on-load what users generally want and expect from modern web apps. Having recently built an almost 100% HTML-based web app, I can tell you the user interactions feel unpleasant. Removing JS from web apps is silly at this point.