FxOS embraced web technologies, but didn't embrace the browser. I think Mozilla is still having a hard time embracing the browser, though at least now the will is there.
Who at Mozilla ever talks about hypermedia? About link text? About navigation? About bookmarks? FxOS was a demonstration of how hollowed-out the philosophy of the browser had become at Mozilla. It used web technologies to faithfully clone non-web UI and OS organization. It would be like reimplementing JavaScript in JavaScript: an interesting intellectual pursuit, but completely useless.
> If anything, the current work to remove XUL and xpcom puts Firefox closer to how FxOS was built, not further away.
Technically yes, but the motivation is different: this is work to make Firefox better, not to make a better-thing-that-is-not-Firefox.
> At the time some employees even build a new desktop browser around the same tech (not the failed Tofino experiment), that was outperforming Firefox because it had a lot of the "new hotness" like e10s and web extensions. Guess what, the desktop team ignored it, only to do the same thing later.
The Firefox Desktop team was too small to pursue much of anything. It was like a dozen people maintaining the Firefox frontend. Progress couldn't happen until the organization was aligned to actually support Firefox.
