The web works by serving documents to users. Normally those documents are html files with data embedded, and they are either built ahead of time (static sites) or built as needed (dynamic sites).
We transferred a lot of the work to the user device, but what if we could go a little further? Why not just serve the data through an API to the user, and let the user's browser built it with html templates that came with the browser, using an embedded static site generator inside the browser.
Some of the benefits I see:
- Only data transferred, faster browsing for everyone;
- Users could choose their favorite templates for sites;
- Better accessibility without extra work for developers;
- Future proof, since there would be no compatibility problems for older sites;
- Most sites should work normally, blogs, social networks, stores and so on.
BTW: I have no idea how WebAPPs would work.