I think the point is rather that single-codebase "productivity apps" that satisfy basic modern experience expectations (like "I could run it offline") are not possible elsewhere - but they should be. And they would be, if some browser vendors cared about the web more than their walled garden.
Also, the thing about expanding the Open Web Platform is that the new features that are available to me don't take anything away from you if you don't want to use them. Keep making static sites if that's what suits your purpose and don't register any ServiceWorkers or any other things you consider "bloat". (As an aside - As fashionable as it has become to moan about Web "bloat" let's strive to remember that the Web standards are debated and governed by committees of consummate experts mostly in the open.) If we expand the Web platform we can both develop "the way we want" (assuming you want to keep doing things the way you have and I want to use new features).