> The situation with Nova (and SimpleMobileTools before it) is that developers are selling their popular projects. This isn't an "Android" thing, but more of an indictment of sustainability of indie FOSS projects.

Exactly this. I bought Nova 10 years ago (December 2015), and I even paid only 10 cent (Google had some absurd sales on apps back then). Till today, I'm using it, receiving updates, and never paid another cent to the dev AFAIK. I don't know how they even financed their business, but even as popular as it was (is?), I doubt they are swimming in money.

I can understand why so many apps end up in subscription-traps, or are selling the whole business to someone else. But at the same time it's insane that as a customer it's really hard to find a useful app, and have a way to continue support on a low level. For example, I probably wouldn't have a problem with paying Nova some dollar every time I switched to a new device, to get a new compatible version. But I can't even do that. There is barely any mobile app iterating this way through the android-versions. So they all are either dying at some point, or end in a trap.