AOA, I agree with much of Sidqi bhai's post, and in fact my own views are evolving past a welfare state as well. I would only add that things can change in the future, as much has changed since a 1000 or 2000 years ago. Humans have always suffered throughout history with the curse of presentism, where they think the present is always the most critical and defining time of history. The fact is that the present is usually always more like the past than any especially unique moment in history.
The present is neither the best of times, nor the worst; but objectively speaking, it is on the whole most certainly better than the past. Public opinion no longer condones things like slavery, subjugation of women and minorities. And generally speaking, these things are enshrined in law, even if they aren't implemented everywhere. It can't be overstated just how monumental these achievements are in the evolution of human civilization. And the critical point here is that the average person in the world today has a more egalitarian worldview than they did in the past; there is nothing, then, to suggest that the average person in the future can't have an ever more egalitarian and ever evolving "Quranic" view of self and the broader society.
To people in the past, it would have seemed wholly idealistic to wish to live in a world where the average person thought it was horrid to buy and sell human beings, or where it wasn't questioned that women have the same right to the public sphere as men. So if something looks idealistic in the Qur'an, it just means to me that we still have a ways to go towards ever higher callings as individuals and societies.