When they choose a real estate investment, of course they already understand in detail about the investment, both the losses and the benefits. You are right, with the current population increase, of course they will need houses for their homes and it would be great if we had a property business, of course it would be very profitable.
While the land has a limit to be occupied for many countries. The value of it increases and that's how it becomes profitable.
As we want to have our own properties and use it for rental as a business, not everyone is easy to afford it. For those that don't have money for downpayment or capital to start, it takes time if you really want to push it.
The weird thing is that we have enough room to house everyone, you can get all 8 billion people, give everyone one house, as in literally 8 billion houses, and it would fit in Africa alone, even without considering other continents and nations. So, I think it's quite important to realize that we are not going to end up with lack of room for development. All you have to do is find good places that will benefit you and you could make a profit from it if you want to.
You just need to be careful where you pick the land, if you pick a land that will gain value in the future, then you could develop housing there and you will make a profit. You can't do that at the center of New York, but you could do that at a farming town nobody lives for now, and in 30-40 years maybe it will be crowded, pick a place like that.