One of the focus areas for this year is IndexedDB. And many of the other areas contain tests for service workers. I don't think it's accurate to say anyone's dragging their feet. Apple's done a 180 on PWAs in the past year. I also don't know what you mean about Firefox dropping pwa support. They've been hard at work improving the PWA scene for years now. And they're docs are the go-to for anyone working on one
It's in their best interest to drag their feet on the issue and ensure that the pwa experience is disincentivised.
As for Firefox dropping pwa support I'm just not sure. It's probably maintenance cost.