One can do all the things that docker does without docker, but the knowledge needed to bring the basic features that docker does is far greater than learning how to use docker. In fact, if you know how to build something remotely close to docker, you'd be crazy not to use docker instead. At the very least, docker brings along industry standard conventions, and builds a common ground for everyone to work on without having to be onboarded on your home brewed packaging, distribution, storage, runtime and networking solution, regardless how simple it is.

On a side note, it seems like many trending topics on HN are heavily bashing new technologies (see k8s, rust, clouds, etc...) that are already widely adopted. Most communicate a resignation from learning something too complex. Docker is not complex, k8s is not complex, rust is not complex; the problems they are addressing are. Most teams developing things that run on the web will have to deal with these problems hopefully before they don't make it. The rest are wizards like the stackoverflow team.

At the same time Gen Z has way more choice and exposure to "computers", so worrying about them sounds very diminishing to their prospects. Sure, adoption of computers, even if they fit your bag or your pocket, is much greater nowadays which leads to way wider range of usages, for better of for worse.

In the end same could be said about the Edison generation and electricity. In the end I barely have a clue how electricity networks operate. Can I experiment with it? Sure. Do I need to if I just want to power on my computer? No.

But more importantly if one thinks of Orwell's 1984, were all printed records were manipulated on a daily basis to reflect a different state of reality while the events were changing, in the days of internet that is not just a tedious sci-fi process but one that can be performed in a fairly efficient and methodical manner to an extent that it cannot be told what was real or not.