I believe Tom Au answered your key question.
Let me just add in response to, "What if someone was just simply rich to buy > 50%, but does not know how to handle the company?"
This happens all the time. Bob Senior is a brilliant business man, he starts a company, it is wildly successful, then he dies and Bob Junior inherits the company. (If it's a privately owned company he may inherit it directly; if it's a corporation he inherits a controlling interest in the stock.) Bob Junior knows nothing about how to run a business. And so he mismanages the company, runs it into the ground, and eventually it goes bankrupt. Stock holders lose their investment, employees lose their jobs, and in general everyone is very unhappy.
I suppose it also happens that someone gets rich doing thing A and then decides that he's going to buy a business that does thing B. He has no idea how to run a business doing thing B and he destroys the company. I can't think of any specific examples of this off the top of my head, but I've heard of it happening with people who make a ton of money as actors or professional athletes and then decide to start a business.