I don't know if you understand what Docker really is when you say something like this: "Run only one process in one brand new kernel", the kernel is shared between containers, that's the whole idea, you package the things your application need and be done with it.
The current problem with containerization is that there are no really good or understood best practices, people are still experimenting and that's why it's a big moving target and, consequently, a pain in the ass if you need to support a more enterprise-y environment. You will need to be able to change and re-architecture things if the state-of-the-art changes tomorrow.
I agree with your sentiment about going overboard on "docker all the things", that's dumb and some people do it more because of the hype than by understanding their needs and using a good solution for it but I think you are criticising something you don't really grasp, these two statements:
> "Run only one process in one brand new kernel"
> you have a kernel in your hand, why the hell you will run only one process on it?
I'm not trying to be snarky, I really recommend you doing a bit more of research on Docker to understand how it works. Also, Docker doesn't make it a pain in the ass to upgrade apps, quite the contrary if you do it in some proper ways.
