In what year was the average, or even marginal person better off? Yes, there may be more income distribution, but would you prefer to be born into a different time under the veil of ignorance?
Even the poorest in our society have incredible access to goods.
Just to list a few:
Wikipedia
Ability to talk to relatives from across the world to little or no cost (Skype and alternatives)
Ability to send money and store wealth cheaply (low cost ETFs, bitcoin, free checking)
Social acceptance of previously marginalized lifestyles
Access to wide variety of foods and entertainment
There has never been a better time to be alive, and I expect that to continue, despite greater inequality.
That is, if the population growth doesn't destabilize the economies and make us revert back to the old times. That's the crux of the issue. The rising tide is lifting all the boats, but we need to make sure the tide keeps rising.
Inequality seems to be deeply encoded in the system. Capacity, in my opinion, only makes sense if you extrapolate from an average human, but there is no such thing as an average human being. However, I don't think it is an exaggeration that our western way of life is not sustainable on a global scale. I wish the fruits of human ingenuity could be enjoyed by every single one of us, but unfortunately it seems utopian.