The reason citizens like you and me are kept around is because we have typically provided some form of economic output, in the form of labor and taxes, to society, and indirectly to the wealthy and powerful class, which is billionaires and politicians.
If most citizens don't have anything to contribute in an economy, they can be eliminated entirely from society so that this class can win the zero-sum games in society, and have natural resources to themselves. Thus, in the best case, commoners will be kept around in government provided housing (with all the things that it implies), with strict limits on reproduction and a very small baseline of resources so as to give the appearance that the government wasn't killing its people, though death would still be incentivized in the form of lower standards of medical care, so that society's dead weight can be eliminated.
In the worst case, politicians and billionaires would simply join forces to eliminate aforementioned dead weight through mass genocide. There is no downside to this, except that the first country to do this may have to face criticism, but I suspect eventually all countries would move in that direction once a few have taken their first step and established precedent.