Instead of having to be content with a few decades of fabulous wealth and power and luxury, the world's rich could extend that experience for centuries and centuries. To a virtually immortal being like that, a regular human would seem like little more than an insect. The life of a serf- and that's exactly how they would see the rest of us- would be worth almost nothing, as they would see dozens or even hundreds of such lifetimes come into existence and then disappear while they went on and on. They would view the rest of humanity the same way we view those species of fly that live for only a single day.
The development of a “whole body transplant,” as this procedure is known, would result in the permanent division of the human race into two separate and highly unequal classes. One class would be effectively immortal and beyond most sorts of consequences, beyond humanity as we know it. The other would toil and suffer to serve the first, without hope of betterment. That would truly be a sick, sad world.