> I think it was important for Mozilla to communicate their Android dev focus was gonna shift to GeckoView, from existing apps
Focus has already shifted for quite some time, though - the current Firefox for Android ("Fennec") code base has already been in maintenance mode since the end of 2017, i.e. over 1½ years, including a few months at the start of 2018 were almost nobody was regularly working on it at all other than watching Bugzilla for any immediate priority bugs and reacting to those in case any happened.
Even if they don't have the entire transition planned out, I think it was important for Mozilla to communicate their Android dev focus was gonna shift to GeckoView, from existing apps, to allow external devs, and customers to have a better plan, even if they don't have the add on strategy and timeline fully fleshed out.
The alternative is waiting a few months to know any of this was happening.