> The developers need to make the apps, otherwise there's no marketplace.

Why is publishing the source code such a burden, when the apparent target are unsophisticated users? Are developers afraid that users will start cloning repos and build their own binaries?

> An App Store (like Apple's) can have strict rules where developers will be banned if they do malicious things.

Apple will rat you out to the cops if you take a picture of human skin on "your own" phone, why should they be a benchmark for anything security or privacy related?