Even if it's more cost effective to own the host machines (whether it be bare metal or VM), I'd guess you still save yourself considerable management headaches

Even if it's more cost effective to own the host machines (whether it be bare metal or VM), I'd guess you still save yourself considerable management headaches if you continue to put containers on them. There is still some stuff to manage with something like puppet and ansible, but I think if most of your configuration is in containers, it gets a lot simpler and these tools become less critical/complicated.