The richest person in the world, whoever currently holds that rank, will always face scarcity. The concept refers to the distance between human wants and available resources. While the resources may be things or commodities, they can also be natural or processed resources.

The area of natural resources, including their processed versions for human use, is the aspect where money and related economic power controlled by one individual are least useful. Clean water is one good example. Humans, like other animals, need clean water (or at least relatively uncontaminated) to drink. Bill Gates cannot control that resource, but he still needs it. He can apply his money toward water conservation and help reduce scarcity, but he faces it along with other earth dwellers.

Medical treatment is another example. If a rich person needs an organ transplant, they might be able to get it faster, including by illegal means. Regardless, the number of available organs that match any individual is governed by the number of organ donors, which leads to scarcity.

Scarcity is also deliberately, artificially created as a business practice. One modern example is toys. Limited production and excessive advertising about specific toys make them very popular and, especially at holiday time, create scarcity.

I would argue that everyone faces scarcity—and that we have widely varying definitions of the word scarcity, depending on our circumstances.

To an unemployed mother of five living in one of the slums of Delhi, it would see ludicrous that Bill Gates considers himself to have a scarcity of resources. For her, finding enough food for her family without resorting to stealing is an endless struggle, and her life is defined by scarcity.

For Bill Gates, scarcity looks different to this. For example, his means are too scarce to allow him to buy a majority shareholding in other technology giants like Apple, Google, or Facebook. While he will never have to wonder where his next meal is coming from, his resources, although immense, are limited, and therefore Gates does experience scarcity.

Everyone in the world faces scarcity.  There are no exceptions.  Even Bill Gates cannot escape scarcity.  Scarcity is endemic to the human condition.

Scarcity exists because people have limited resources but, at the same time, have unlimited desires.  We people tend to want many things, but we do not have unlimited resources with which to fulfill those wants.  This is true even of Bill Gates.  Let us imagine that Bill Gates wants to buy a certain island.  He might not be able to because the island is not for sale.  The owner of the island may love the island and may not want to sell it for any price.  In addition, even Bill Gates could not buy absolutely everything he might want to buy.  For example, Bill Gates could not come anywhere near to buying up all the shares of Apple or Google.  Those companies are worth much more than Gates’ net worth.  When Gates invests in the stock market, he cannot buy everything...