Here in the US and many other first world countries the population is getting very old. We'll need to bring in younger people who look different to keep the average age down. This obviously has all sorts of side effects. The other problem is the wealth inequality it creates. Wealth compounds with time plus the older generation grew up in a boom period. Add in the fact that they were able to buy cheap housing which has appreciated by a large amount and are effectively blocking new affordable housing from being created in many areas (NIMBY's) and we have a very interesting predicament.