I agree with everything Andrew says here. Progressive web apps are great, but as long as Google heap praise on mobile-only solutions (like the Washington Post doorslam) and also encourage separate AMP sites, they’re doing a great disservice to the web.
More features arrive regularly to make this “one web” even better and easier to maintain. Service worker, streams, app manifests, payment request, to name a few. But adding these features one at a time to large, mature applications like WaPo or FT or Nikkei is a slow and painstaking process. That’s why it’s taking us a long time for us to tick off all these new features, and why it seems like madness to try and build the entire app several times over.
However, by creating the concept of PWAs and marketing them as they do, Google is encouraging publishers to ‘start again’. And they’re doing exactly the same thing with AMP.