Why bugfix versions are stalled forever?

We are a team that uses a lot alpine for development (dockerized servers) but for production we are still reluctant to provision Alpine, mostly because an unclear release and bugfix versions roadmap, there are plenty of versions with their latest bugfix version abandoned, even being 60-70% completed according to the redmine, but they are not simply released. The most worrying is that some have reached 100% and they are not released. It's better to release the 60-70% of bugs solved than not releasing ever. Any thought on why is that?