"Doing an IE6" for Google would be quite different from what Microsoft did, who wanted the desktop to stay relevant. For Google the web is just an advertisement platform. If/When Firefix is gone, they will hold all the cards. "Doing an IE6" might mean removing support for ad-blockers. Or making Google DNS mandatory. Or have everything you do on the web be phoned to Google, to improve your advertising experience. Assume they will find creative ways to monetize the web, ways that we didn't even think of yet. If you thought the web in 2019 was bad, beware of the Google Future.