Getting rich should just by a byproduct of bitcoin. If you believe in bitcoin and have chosen to invest time and money in it then maybe the may get rich eventually depending on how many coins they have and hold, though it's not a guarantee and I don't think people should be getting into bitcoin just to be rewarded this way though that's up to them. As for the limit, there is no limit but that will be dictated by the market and supply and demand and obviously how many coins they hold.