Docker images is a simple quick-and-dirty packaging solution with all the pieces necessary (building, versioning, storage and deployment). I believe this is why

Docker images is a simple quick-and-dirty packaging solution with all the pieces necessary (building, versioning, storage and deployment). I believe this is why it won. Don't think any of those other options had anything similar. The alternatives, like building and deploying apps with native OS packages (e.g. .debs) were significantly more complicated and less portable. (While it's not that Docker images are better than native packages, they're doubtlessly generally easier.)