Google themselves launched or re-launched five Chrome-only sites last year (Hangouts, Meet, Adwords, Earth, and Allo). Six if you count the Google Advanced Protection Program.

Google Flights began blocking Firefox for Android last week, and Google still serves a degraded Search experience to Firefox users on Android (but hey, no AMP).

Despite well-meaning concern from the Chrome team, it's abundantly clear that Google's other product managers do not view interoperability with open, cross-browser standards as a requirement. And while many products eventually gain Firefox support, that support usually only comes months after launch, if at all. To wit, Earth was recently rebranded from "Earth on Web" to "Earth for Chrome," so who knows what's going to happen there.