Docker is quite closed as well, so I am not sure if it is a good step in the right direction.
If Docker were an open system it would already be running natively (not that ridiculous docker-in-a-vm thing) on Solaris, FreeBSD (which have offered similar functionality for decades), and probably MacOS by now. Instead their maintainers are actively hostile to portability patches as a matter of policy.
systemd is also open.
Open (as in "open source") != modular (or "inherently portable" for that matter).
Open alternatives already exist, I use them. But people build other systems that integrate only with docker, and since docker deliberately refuses to follow any fixed standard, other systems can't be compatible with the docker ecosystem. Am I supposed to fork every codebase in the world?
I could have sworn there has been even a few instances of Systemd cock blocking Docker even though Docker had a clear precedence.
I have historically had many problems with Docker and how the project is governed. I'm also no fan of systemd. But there's no point in literally spreading lies.
Worst trouble I had with it was compiling the necessary modules into the kernel when I installed it. The rest was relatively painless (as painless as administering a Gentoo system can be, anyway).
Your post needs a huge dose of clarification.
But you could even use Docker before all this new stuff by putting in developer, install Crouton but you had to use rkt to launch the Docker containers but worked fine.
With ChromeOS 67 no longer necessary.