I dunno, if it wasn't for Safari we'd all be Progressive Web App developers, but they're years behind on implementing common sense standards.

Depends on the target market, Apple devices aren't that significant everywhere and most companies aren't multinationals.

Safari, the great underdog, the equalizer.

Alas Firefox has been rather joining up on the axis of "we refuse to implement basic stuff" bandwagon.

Oh and meanwhile Microsoft is doing really good & helpful work to improve the web platform. In seemingly very very altruistic ways. (Which is how I feel Google is 98% of the time operating too!)

A lot of the time Firefox’s reticence to implement things is because they don’t think it’s the right thing to implement.

HTML Imports, for example, were something that everyone wanted, but Firefox developers looked carefully at it and pointed out some very serious problems that weren’t immediately obvious, where implementing HTML Imports would cause a lot of trouble down the track, limiting future extension possibilities. So they said, “let’s hold off on this, wait until we get ECMAScript modules and related loading stuff sorted out, then we can look into redesigning this”. They convinced the Chromium developers, and so they steadily removed it before it could grow too many roots to remove.

This is quite different from Safari’s implementation lethargy, which is typically just opaque.