A century ago, the predecessors to today's progressives explicitly described a lot of the human species as suboptimal, and they advocated improving the breed. H.G. Wells, for example, wrote: http://www.gutenberg.org/files/19229/19229-h/19229-h.htm

The new ethics will hold life to be a privilege and a responsibility, not a sort of night refuge for base spirits out of the void; and the alternative in right conduct between living fully, beautifully, and efficiently will be to die. For a multitude of contemptible and silly creatures, fear-driven and helpless and useless, unhappy or hatefully happy in the midst of squalid dishonour, feeble, ugly, inefficient, born of unrestrained lusts, and increasing and multiplying through sheer incontinence and stupidity, the men of the New Republic will have little pity and less benevolence. To make life convenient for the breeding of such people will seem to them not the most virtuous and amiable thing in the world, as it is held to be now, but an exceedingly abominable proceeding. Procreation is an avoidable thing for sane persons of even the most furious passions, and the men of the New Republic will hold that the procreation of children who, by the circumstances of their parentage, must be diseased bodily or mentally—I do not think it will be difficult for the medical science of the coming time to define such circumstances—is absolutely the most loathsome of all conceivable sins. They will hold, I anticipate, that a certain portion of the population—the small minority, for example, afflicted with indisputably transmissible diseases, with transmissible mental disorders, with such hideous incurable habits of mind as the craving for intoxication—exists only on sufferance, out of pity and patience, and on the understanding that they do not propagate; and I do not foresee any reason to suppose that they will hesitate to kill when that sufferance is abused. And I imagine also the plea and proof that a grave criminal is also insane will be regarded by them not as a reason for mercy, but as an added reason for death. I do not see how they can think otherwise on the principles they will profess.

The only way I could see of seriously addressing the problem while remaining true to progressivist principles would be a global eugenics program overseen by a democratic world government.

This is a good illustration of the difference between how Progressives and NRx approach problems.

First a Neoreactionary would point out the obvious problem with this approach: you have democratic governments attempting to implement eugenic policies which will affect what the future voters will be like. Thus this system has a very strong and undesirable attractor, namely the politicians eugenically breed the kind of people who will reelect them.

The NRx approach to dealing with proliferation of low time preference people is to reduce/eliminate the welfare state and let them die out as a natural consequence of their own short sighted behavior.