Apple has a vested interest in pushing users towards their walled garden for apps, while Google and Mozilla are trying to bring app-like experiences to the browser. There are hints of Safari supporting serviceworkers but I'm not holding my breath.
Highly recommend Alex Russel's talk on progressive web apps as background: https://m.youtube.com/watch?v=x7cfLDFVyHo
I happen to agree that offline-readiness (via service workers) is at the core of whether the open web will continue to be a relevant medium.