Your "very, very easy" proposal just got a little more complex. For instance, ServiceWorkers only work in Chrome and Firefox, which means no iOS support for you

Your "very, very easy" proposal just got a little more complex. For instance, ServiceWorkers only work in Chrome and Firefox, which means no iOS support for your web app. I currently work on a web app written with AngularJS and PouchDB. We're constantly facing issues that would have been easy to deal with in a native app. I'd argue it's just as hard writing a good web app as writing a good native app. It's just a different set of challenges.