That's effectively how Fedora and other major Linux distros handle it - ABI breaking library changes are landed long before a given distro release is declared stable, giving time to mainteiners to rebuild and potentially also fix their packages.

It's a bit easier due to all the packages being open source, so the maintainers who do the ABI break generally rebuild the dependent packages. We still do that basically manually in Fedora but AFAIK OBS can do this automatically.

But even on Sailfish OS nothing (other than missing infrastructure for Jollla Store and Open Repos integration) really prevents this from working with open source apps. You would just import srpm or spec and tarball instead of the binary RPM, then when a new target shows up some time before release, the app would be rebuikd automatically. Most would rebuild just fine, some might need to by fixed by maintainers.

In any case a system like this could help save precious maintainer resources and prevent user facing app breakage.