5. What do rich people do: as is already normal. When you see that a business or profession that is popular with many interested parties would have to make some estimates that saw everyone else doing it doesn't seem he was rich rich.
5. What did the rich people do: Naturally, when the business or profession is gaining popularity. It would have made a lot of interest to me about seeing other people rich. I want to be rich like him
5. People rich do?: naturally, when that business or career is popular. There will be many who are interested to do about that other people do become rich, want to be rich like him.