Although the essay begins as though he is advocating for leisure for some privileged section of the society -- and one might especially suspect his position is thus given he himself was part of the old aristocracy by birth -- he explains not only that idleness being a collective right will elevate the society but also that it can be achieved. The time to have achieved it, in my opinion, has already passed and yet we continue to be "foolish", as he puts it.
His argument is so cogent that the following lines seem completely within reach for the society and paint the idea of paradise"
>>> In a world where no one is compelled to work more than four hours a day every person possessed of scientific curiosity will be able to indulge it, and every painter will be able to paint without starving, however excellent his pictures may be. Young writers will not be obliged to draw attention to themselves by sensational pot-boilers, with a view to acquiring the economic independence needed for monumental works, for which, when the time at last comes, they will have lost the taste and the capacity. Men who in their professional work have become interested in some phase of economics or government will be able to develop their ideas without the academic detachment that makes the work of university economists lacking in reality. Medical men will have time to learn about the progress of medicine. Teachers will not be exasperatedly struggling to teach by routine things which they learned in their youth, which may, in the interval, have been proved to be untrue.