> No, everything was already open source, other had done it before too, they just made it in a way a lot of "normal" users could start with it, then they waited too long and others created better/their own products.

Yes. It was a helpful UI abstraction for people uncomfortable with lower level tinkering. I think the big "innovations" were 1) the file format and 2) the (free!) registry hosting. This drove a lot of community adoption because it was so easy to share stuff and it was based on open source.

And while Docker the company isn't the behemoth the VCs might have wanted, those contributions live on. Even if I'm using a totally different tool to run things, I'm writing a Dockerfile, and the artifacts are likely stored in something that acts basically the same as Docker Hub.