Distributors entering Flatpakland

Did the tool you use to make runtimes and apps survive? How did you deal with not having things like apt/dpkg in the app containers? Sounds like you didn't have a large .deb app package community to start with, so I think your situation would be different to Debian. Switching Debian to package things as flatpak instead of .deb wouldn't scale and would alienate folks who dislike flatpak, while auto-convert would be doable for us I think. What kind of fragility did you see?