Some of us badly need and want it - others not at all. But if such insurance is imposed upon those who do not need it or wish it and covers those who, ab initio, gave up no resources and did not invest work or effort in obtaining it - it is immoral. Such insurance is bought and paid for with a restriction of our freedoms and liberties. This, in effect, is the essence of most of the modern welfare programs. This is not to mention the practical problem of how to measure differences in natural endowments, how to distinguish them from acquired ones and who will determine what should be included in the list of natural disadvantages.
Capitalism works, on the whole.
Its truth value is substantiated by its continued existence and success. The Libertarians adopted this view of human inability to dispense with justice by establishing a just pattern of distribution. Instead of imposing a pattern on society, they limited themselves to ascertaining that the market players engage in just acquisitions and in just exchanges. Justice is not dependent on a particular distribution pattern, whether as a a starting point, or as an outcome. If the position of others is not worsened by the acquisition - then it is morally permissible.