When the robot revolution happens, we need to have many supporters of efficient charity among the ruling class

The problem is much worse. All the ethical sophistication in the world (as argued by e.g. Richard Rorty) can not in practice serve as a barrier to cruelty and domination if there's no underlying moral sentiment of empathy, of sharing a certain "human circle" with your fellow beings.

The ruling class needs to share some moral emotions that would allow preference-utilitarian/negative-utilitarian ethics towards the "worthless" poor in the first place. Otherwise they might simply decide that the "efficiency" in "efficient charity" is best achieved by enslaving the former working class or lumping it with domestic animals... for the proles' own safety/virtue/moral benefit/etc, of course. They're dirty and uncouth! they would revert to "savagery" without proper control! they have no use for the liberties that the superior man enjoys! empathizing with them as equals is simply an intellectual mistake and naive sentimentality! ...Basically, see every rationalization for slavery ever made; when slavery cannot be opposed by force or starved economically, those aspiring to become the new "aristocracy" could grow very enamored of such rationalizations again.

I can hardly even begin describing my fears of how the new technocratic/quasi-aristocratic elite might conduct its relations with the "common people" that have no economic or military leverage over it. This is why I am so fucking terrified about the emerging association between transhumanism and an anti-egalitarian/far-right ideology!

The Jacobin magazine has a very good article on this subject from a while ago:

The great danger posed by the automation of production, in the context of a world of hierarchy and scarce resources, is that it makes the great mass of people superfluous from the standpoint of the ruling elite. This is in contrast to capitalism, where the antagonism between capital and labor was characterized by both a clash of interests and a relationship of mutual dependence: the workers depend on capitalists as long as they don’t control the means of production themselves, while the capitalists need workers to run their factories and shops. It is as the lyrics of “Solidarity Forever” had it: “They have taken untold millions that they never toiled to earn/But without our brain and muscle not a single wheel can turn.” With the rise of the robots, the second line ceases to hold.

The existence of an impoverished, economically superfluous rabble poses a great danger to the ruling class, which will naturally fear imminent expropriation; confronted with this threat, several courses of action present themselves. The masses can be bought off with some degree of redistribution of resources, as the rich share out their wealth in the form of social welfare programs, at least if resource constraints aren’t too binding. But in addition to potentially reintroducing scarcity into the lives of the rich, this solution is liable to lead to an ever-rising tide of demands on the part of the masses, thus raising the specter of expropriation once again. This is essentially what happened at the high tide of the welfare state, when bosses began to fear that both profits and control over the workplace were slipping out of their hands.

If buying off the angry mob isn’t a sustainable strategy, another option is simply to run away and hide from them. This is the trajectory of what the sociologist Bryan Turner calls “enclave society”, an order in which “governments and other agencies seek to regulate spaces and, where necessary, to immobilize flows of people, goods and services” by means of “enclosure, bureaucratic barriers, legal exclusions and registrations.” Gated communities, private islands, ghettos, prisons, terrorism paranoia, biological quarantines; together, these amount to an inverted global gulag, where the rich live in tiny islands of wealth strewn around an ocean of misery. In Tropic of Chaos, Christian Parenti makes the case that we are already constructing this new order, as climate change brings about what he calls the “catastrophic convergence” of ecological disruption, economic inequality, and state failure. The legacy of colonialism and neoliberalism is that the rich countries, along with the elites of the poorer ones, have facilitated a disintegration into anarchic violence, as various tribal and political factions fight over the diminishing bounty of damaged ecosystems. Faced with this bleak reality, many of the rich – which, in global terms, includes many workers in the rich countries as well – have resigned themselves to barricading themselves into their fortresses, to be protected by unmanned drones and private military contractors. Guard labor, which we encountered in the rentist society, reappears in an even more malevolent form, as a lucky few are employed as enforcers and protectors for the rich.

But this too, is an unstable equilibrium, for the same basic reason that buying off the masses is. So long as the immiserated hordes exist, there is the danger that it may one day become impossible to hold them at bay. Once mass labor has been rendered superfluous, a final solution lurks: the genocidal war of the rich against the poor. Many have called the recent Justin Timberlake vehicle, In Time, a Marxist film, but it is more precisely a parable of the road to exterminism. In the movie, a tiny ruling class literally lives forever in their gated enclaves due to genetic technology, while everyone else is programmed to die at 25 unless they can beg, borrow or steal more time. The only thing saving the workers is that the rich still have some need for their labor; when that need expires, so presumably will the working class itself.