Docker has a lot of quirks and rough edges that may be attributed to its history. It was open-sourced rather hastily from dotCloud, and caught on largely due to

Docker has a lot of quirks and rough edges that may be attributed to its history. It was open-sourced rather hastily from dotCloud, and caught on largely due to its appeal as an easy-to-use, open, and complete package for containerisation, unlike other containerisation ecosystems that already existed. In some ways it's an example of a "worse is better" solution (which is not a bad thing). Some of the things you mention are just the typical sort of bad design decisions that get made without the benefit of hindsight. I'm sure we have all made similar missteps while designing systems. It's also true that some of these flaws made it more approachable, and actually helped with adoption. For example, a reproducible image build would be great, but it would not be as easy for a newbie to throw together as a quasi-shell-script Dockerfile that lets you run whatever non-reproducible commands you like. That less-opinionated disposition of Docker was part of what made it easy to pick up. In the near future we will probably see a new containerisation ecosystem rise with an overall better design and more disciplined approach. Docker will always have its place in history as the implementation that made containerisation mainstream.