Who is he going to staff it with? There is zero chance he will cook and clean for himself and he will need a substantial army to protect himself from the collapse of the human race.
If he goes with people how long before the security guards realise they can dump his scrawny ass off a cliff and have a better quality of life as money becomes irrelevant? If he goes with robots how long before they break beyond what they can self repair? If he goes with robots with human engineers, how long before the engineers realise the same thing as the security guards and program the robots to kill Bezos?
But how do you pay the overseers to enforce it when money is no longer valid? And the overseers are bigger and tougher than your average billionaire?
Slavery only works when there is money to pay the overseers and a legal system to protect the owner class from being extorted by the overseers.
ICE is in a similar boat and they have to pay significant amounts to attract people to carry out ICE fascism.