The problem with doing a client for this is lack of scale. Assuming there's 100k active users, 50% run iOS/Mac, probably < 10% of those would pay for an app. I'm thinking ~5k copies which sucks compared to the effort required.
@pth A straight up tootclient, doesn't carry much value in the Fediverse. The value of any social network are the users. Only a client that adds value in itself that people actually want - top notch UX, new original features,... - may yield revenue for a while. Remember IRC? Yeah, this has happened before.