I stopped watching at the 8 minute mark because it's a moot point. For this to be a realistic scenario (for Chino's question, that is), you need realistic circumstances. First off, a few hundred individual drivers (hell, even then, that's a pretty small amount), not the handful that they have; you also need real-world circumstances...new drivers, dipshit people who drive while talking, texting, inebriated, children in the back screaming at each other and pooping all over the place, your wife giving you road-head (or prostitute, of course, duh), etc.
If this were implemented in the US, despite every opportunity to learn the ways of the roundabout, there'd be people driving up to it freaking out because they didn't learn and/or weren't taught properly. I mean hell, I encounter people
every single day that still do not get a four-way stop; zero exaggeration there. The four-way stop has been a thing since most drivers who aren't wrinkled up and blind were born and people still can't keep their shit together. Keep in mind...I'm in Texas.
I get it for their 'myth-busing' purpose, but for your question, Chino...it's kind of useless and doesn't answer the question properly even a little. In my opinion, the true answer is: Cause 'murica. We have to do shit different just for the sake of doing so for almost every aspect of our society, it seems...
even if it's undeniably worse.
(YES, I AM A TRUE PATRIOT)