The thing is that the dollar as no value by itself, its value derives from what it could buy. If the economic activity increases generating more value, the value of the dollar will increase. And that's not just theory, that's what happened in the last 20 years were a large number of population in developing countries were raised out of poverty. Check the Milanovic chart for seeing it [1].
The second problem is that it is not necessary that a society that has an unequal wealth distribution is also unjust. Suppose to have a society where everybody between 20 and 60 years old works for 1K a month. Before 20 years old the could use debt to leave, after 60 years old to their death (let's say 80 years old) they live with the savings. You would agree that this society is just, everybody makes the same amount of money. And yet there is inequality in wealth distribution. Youngs just before turning 20 will have a huge debt, people turning 60 will be, conversely, in the top 1%.
This example could sound naïve, replace it with student loan and pension funds and you will see that is pretty much the status of US economy.
[1] http://blogs.ft.com/off-message/files/2013/10/Change-in-real...