Yeah... except if you look at how many people are actually developing the language, it's mainly just one person, though I can't ignore that there are some other people that do create pull requests, but the majority of commits are from jens.
Also, that video you linked got many stuff wrong, and skipped most of the actually important parts. If you want to see everything the video got wrong, just find my comment on the video (that I made 3 months ago, because I've already seen it before).