You can disable all phoning home. Have a look at https://support.mozilla.org/en-US/kb/how-stop-firefox-making...

Having a single setting that does all of this would indeed be nice.

https://gist.github.com/ryandaniels/33e443bb401dde665fce15dd...

but yes, a single setting is necessary if you want to also opt out of any _future_ telemetry settings without always having to update your prefs.