First, I think service workers are essential if we don't want all future apps to live and die by arbitrary app store restrictions. Service workers provide a lot

First, I think service workers are essential if we don't want all future apps to live and die by arbitrary app store restrictions. Service workers provide a lot of functionality that make web pages competitive (feature-wise) with apps. Second, I'm sure you've seen plenty of implementations that were just fine, you just didn't notice. Angular comes with a default implementation that does caching and plenty of sites use it.