Well, perhaps because such provisions cannot possibly be given to all, in equal quantity and quality. Yet, of course, that very same problem faces egalitarianism when it comes to the so called basic necessities. There is scarcity in food, education, health care (e.g., in the supply of professionals, equipment, and materials), etc., etc. At any given time only so much of these benefits is being produced. Perhaps they could be increased with some nudging or outright coercion but even that cannot make them available to all and usually backfires so shortages are the result. And any effort to ration is going to involve major unequal features, such as the blatantly unequal power to impose the rationing that some will have while others lack.