An ideal picture of the economy, in which the thesis that "a large number of billionaires indicates a rich and developed economy", in an ideal picture from a textbook, is possible and correct. But on the other hand, the proportionality of the number of billionaires to the reduction of the number of poor in the country has a huge number of errors, which reduce this whole theory to a factor of impracticability in real life.
The "billionaires - number of poor people" equation does not include inflation and the purchasing power of a constant $30, which have different values in countries around the world.
The economy is flexible, so $30 in India is not at all worth $30 in Spain.
And this is important because it is very difficult to average money. The second factor that brings out the formulation constant is the existence of state capitalism in the economy, which implies poverty regulation methods and the number of billionaires, since administrative-state capitalism has a lot of levers of influence on the economy. The third factor is the existence of the shadow economy, uncontrolled cash flows from criminal businesses, smuggling, corrupt transactions and methods of hiding capital, which affect statistics that do not take these values into account, even though they are involved in all economic processes. But if we take purely statistical data on the growth of billionaires, then we can reduce all these examples to the values of a small village where a thousand people live.
If in one year there were 2 rich people out of 1,000, and the following year there were 3 rich people out of 1,000, then the number of the poor decreased accordingly, as well as their economic condition.