Re-writing the app to support a different site isn't a small undertaking, so I don't blame devs if that isn't on their immediate roadmap.
Some devs, such as those of Sync and RIF have already said apps for other sites are in development, too. Sync for Lemmy and RIF for Tildes.
Then there are new apps entirely that will arrive built for the new sites. Jerboa is great already, even with the extremely short time it's had to be developed in.
Oh wow, so it can! Either that's a recent feature, or I'm not very observant (probably the latter), as I hadn't seen that option before. Thanks!