CoreOS and RancherOS have shown how everything can either be built into the base OS image or running in Docker, with no system packages needed.
I think this had been shown somewhat before the time of these whippersnapper distros (Slackware, LFS etc), indeed before the days of RPM, make && make install directly on production servers were how things were done.. and it was not good.
Also; in the case of CoreOS, the base image is still built using a package manager (portage). Not sure about that other guy.