Land is considered as safest asset, no chance of volatility of prices. Means one time investment give more profit plus additional benefits. Risk of loss is very low, they used land for multi purpose like lending, housing, fishing or can convert it as resort or picnic point etc. Moreover its worth also increases side by side. These attractive ideas generate more profit for them. And the good thing is that these assets can transfer to their generation with increases value. Although land requires higher investment or or it requires long term return. Billionaires have the ability to bear both of them. Hence it is an assets that allows tye owner to expand their wealth over the time.
Land is the most profitable investment in almost every era and there are many benefits which people can get from investing in land. Billionaires invests in land because they have required capital available to invest in land and they are also full aware of profit they can get from investing in land. If you choose a land wisely for investment then there is huge possibility that value of that land never depreciate in future. The land you own can be used for generating passive income in form of rentals. You don't need to be a billionaire to invest and get good profit from land, if you are smart and can foresee future of a land that is cheap now but will go up in future then you are on path of success.
The difference between us and big men who have that huge wealth when it comes to landed property is that, they can see what tomorrow looks like, money gives them that ability, poverty only allows you to see today. The big men will grab any available land near strategic places like close to waterside and roads because they can project the commercial value. Lands that regular people like us will look at as a bushy area and not worth our time or investment, a big man will likely see it as the best investment because they will project like ten years ahead. No broke person can do same thing because you can buy a land now to keep for a long time but as soon as you buy the land, the next month you are broke and need money.