Apparently someone has, because I was using Chromium on Linux to watch Netflix several years ago without any trouble (this was before Firefox got it working).

Are you sure it wasn't using Chrome's implementation?

Actually, you're right, it was Chrome now that I think about it. It's been a while.

Before I canceled my Netflix subscription (due to lack of use), I was using Firefox to view it.

The same people who were motivated enough to get it into Firefox?