Is general knowledge important?
Napoleon Hill in his book Think and Grow Rich shares a story about Henry Ford. While Hill was gathering material for a book about how to become wealthy, he took an opportunity to analyze the famous automaker.
Henry Ford was in court suing a Chicago newspaper for libel. The newspaper called him "an ignorant pacifist" because he had very little education. Ford defended himself by asking why it was necessary to clutter his mind with general knowledge for the purpose of answering questions that did not concern his objectives. All he had to do, he explained, was push a button on his desk and he could summon to his aid men who could answer any question he posed.
Well of course that may make sense when you're already rich and at the top of your field, but you have to get to that position first. The more general knowledge you have the more options you have. Plus there are other considerations. If you're having children, having a good knowledge base will better allow you to educate them. At the end of the day, you'll never know when knowing more than the next person will separate you and put you in a good position to succeed. There is no such thing as having too much knowledge.
On the topic of that video. I think that shit is a little fake. It seems like the chick in the middle was just giving nonsensical answers to play into the theme. She would basically botch an easy question horribly and then nail one that was much harder. It just came off as rehearsed.
Henry Ford was on the bottom of society when he decided to ignore everything that did not have to do with mechanical engineering. His focus on only one thing is what allowed him to master it and become one of the richest men in history. In short, his singular focus is what made him rich and powerful.
Young Michael Jordan used all of his free time practicing basketball. Now imagine if young Michael Jordan would of used his basketball practice time to practice basketball, golf, and baseball at the same time. Singular focus is the reason why Michael Jordan is Michael Jordan. He played other sports sometimes, but his main focus was basketball.
A person who only masters one thing can use their mastery of that one thing to acquire resources that allow them to get any other knowledge and resources they need from other fields.
In the grand scheme of things, the people you just named are nothing. Henry Ford didn't invent shit. All he did was revolutionize the production of an up and coming product. MJ was really really good at what amounts to playing a game.
People like Leonardo Di Vinci and Benjamin Franklin have been praised for centuries, and these dudes didn't just get good at one thing. They had huge bodies of general knowledge and strove to master several subjects. In fact, from the Renaissance on, that's pretty much what separated people considered "Great" from everyone else. That's what the term "Renaissance Man" means. It's someone who has a variety of skills and strives to be competent in many areas. This idea that you have to dedicate yourself singlemindedly to something to be successful is a relatively new notion and has more to do with the desire to make money than it does with attaining success in a particular area.
I'm not saying applying yourself whole-heartedly to a particular endeavor is bad, but it's a bad argument to point out a couple guys that took that approach and made a lot of money as some kinda proof that that model is the best for everyone or just in general.