I would also like to live in a world where it is easy for end-users and distros to theme apps. But with current technologies and cultural expectations this results in an untenable testing and support burden on app developers.

We could shift cultural expectations so that distro maintainers become the first tier of support for all app issues in their distro, and escalate issues to app developers if and only if they've confirmed that the issue is distro-agnostic. That would be sustainable for app developers but could be a heavy burden for small distro teams.

> This is a HARD problem, but that isn't an excuse to not face it.

Agreed, I just don't think it's the responsibility of app developers to solve.