HTML6 proposal for single-page apps without Javascript

There’s a standard design pattern emerging via all the front-end javascript frameworks where content is loaded dynamically via JSON APIs. This is the single-page app web design pattern. Everyone’s into it because the responsiveness is so much better than loading a full page - 10-50ms with a clean API load vs. 300-1500ms for a full HTML page load. Since this is so common now, can we implement this directly in the browsers via HTML so users can dynamically run single-page apps without Javascript? My goal would be a high-speed responsive web experience without having to load Javascript. This could probably be done by linking anchor elements to JSON/XML (or a new definition) api endpoints, having the browser internally load the data into a new data structure, and the browser then replaces DOM elements with whatever data that was loaded as needed. The initial data (as well as standard error responses) could be in header fixtures, which could be replaced later if desired. The HTML body thus becomes a tempting language, with all the content residing in the fixtures that can be dynamically reloaded without Javascript.