yes, it's unfortunate, but the world changes...
The way forward is likely two fold;
a) an increasing emphasis on PWA's rather than installed apps. The result is the same, but PWA management is a lot simpler than apps.
b) switching to Cordova instead of PhoneGap. (They're much the same thing, PhoneGap is based on Cordova). One can install Codova locally, but I suspect some sort of "Cordova as a service" (aka PhoneGap Build) may also spring from the ashes.
Cheers
Bruce