How do we keep apps maintained on Flathub? (or building a more respectful App Store)

There have been a few discussions about what Flathub should do to push developers to maintain their apps on the latest versions of the published runtimes. But most of those lack important details around how this would actually happen. I will not discuss in this post the technical means that are already in place to help developers keep their dependencies up to date. See the Flathub Safety: A…