Actually, this is not a good way of thinking. Because Bitcoin is never going to be special to rich people in the future. The poor or the middle class are always going to be able to make an investment whatever they would like. There is no such goal for Bitcoin like it is going to be used by only a group of people after a point. If there was such thing, it would be really ridiculous. And the interest in Bitcoin would go down sharply. And this would even end Bitcoin in time.