No, creating M packages x N OSes is exactly what we do. In fact, we create M+N package-managers x N OSes - and then also create MxN packages.

If you can write a language-specific package manager for all OSes, you can also write a non-language-specific package manager for all OSes, so I the "it doesn't work in all distributions" argument is just a symptom of my complaint. Instead of working towards a cooperative packaging solution where the effort of packaging can be re-used, we continue to create more and more special snowflakes and fragmentation.