gnu and linux have done the unthinkable, being very longevity and living very long woa!! they have been important!! and xmpp and irc are longevity too! but will f-droid have longevity too?? will it live for 40+ years?? android too?? both of them are open source so anyone can fork them and keep them alive yea!! n.n
The latest is that Google is making it easier for external stores. This was in development before their recent court loss against Epic. F-Droid is still going strong imo, although it’s certainly lacking as a place to browse for apps.
If F-Droid did die something would definitely pop up in its place. It already has a protocol that allows you to monitor other app sources than the official F-Droid store, such as directly from developers. Hell, there are already alternate versions of the F-Droid app, eg AuroraDroid.
All F-Droid does is vaguely check the app and then compile it with their key. They’re simply a single point of trust for this action, a buffer between the user and the many developers writing apps. This is a service anyone could provide, however right now no one else needs to because everyone trusts F-Droid well enough for most things, and their favourite app developers enough to update directly.