One thing we've found when attempting to respond to people who assert that (for example) the encyclicals say not one word about the importance of widespread capital ownership is that they are never at a loss for a rationalization for their position. Even explicit statements in the encyclicals are not to be taken as explicit statements, because later encyclicals presumably say exactly the opposite!
That, at least, was essentially the response we got when we posted the original of yesterday's comments. That forced us into the position of having to point out to our correspondent that what she was saying could not possibly be the case.
The encyclicals that followed Quadragesimo Anno and Divini Redemptoris expand and elaborate what was laid out in Rerum Novarum, but they do not — and cannot — contradict it, or we'd be admitting that the Church changes its teachings, which (if you subscribe to Catholic teaching) can never be the case. Even for non-Catholics who apply common sense to the discussion, it is hardly likely that an institution that claims it never changes its teachings would do so deliberately.
The fact is that Leo XIII was addressing a problem that had been growing in magnitude since the 15th century when, after all the progress that had been made since the so-called "fall" of Rome, ordinary people began to lose capital ownership. People tended, however, to retain their political rights, especially since the ruling elite (both political and economic) realized that without capital ownership, political rights mean nothing. As Daniel Webster observed during the Massachusetts Constitutional Convention in 1820, "Power naturally and necessarily follows property."
The consequence was that by 1891 you had a large number of people in the world who had equal political status, but unequal economic status. They therefore lacked the power to restructure the institutions of the common good, the flaws in which were causing so many problems.
The only way to have the political power to restructure the social order is to have the economic power that ownership brings. This mandates widespread capital ownership if you want to have a just society.
In the meantime, however, you can't let people starve or suffer ill-treatment. That mandates increased levels of charity, even imposed living wages, benefits, and State welfare until such time as the great mass of people achieve capital ownership and can take care of themselves.
The problem, however, is that not only have most commentators mistaken short term expedients for the solution, they have not even implemented the expedients, sometimes for good reason, other times because they mistake the emergency measures for the solution, and can see that they are destructive when instituted on a permanent basis, as the current global economic and debt crisis has shown.
Consequently, the popes after Pius XI have stressed the emergency measures over the ultimate goal simply because you've got a victim bleeding to death and that takes precedence — what some call the law of the urgent over the important.
Thus, private property is at least as important as it ever was (more, considering that virtually nothing is being done to advance it, and the global situation is about ready to implode), but you have an emergency on hand that isn't being addressed. That is the point of the later encyclicals, not a change in Catholic social teaching.