Static vs dynamic linking is an implementation detail as far as I'm concerned. If all the dynamic libs needed were in a well-defined location it wouldn't matter that much.
As for where configuration and data live, that's always available in the docs, and Linux convention puts stuff in /etc, so I'm not sure how containers help. And dynamic libraries are in a well-defined location, with environment variables and other tools that allow you to specify where they live. It's not like dynamic linking is an unsolved problem.
There are just fewer things that can go wrong when you get to a sufficient number of services. And lastly moving to a new host is infinitely easier too, export the volume, import of new host and off you go. And stuff like Kubernetes will just handle this for you (and more).
And as for those linux conventions, they vary a lot from distro to distro, you can never be quite sure where that specific version of that specific distro puts its files. So having them just not be able to touch the host ever is a good thing.
As for your second paragraph, that's very idealistic. Config can live in /var, /usr, /home, /usr/local, literally anywhere. I find it much nicer when all data / configuration for a piece of software is all self contained.