The issue is those closer to the money printer get the biggest rewards (according to the US Fed’s description of their stakeholders) so as they increase their supply of currency they can accumulate more goods, outpacing the rest of the classes which have to suffer through inflation, which debases their money, keeps wages low and goods prices increase

In an evenly distributed and fully observable currency supply which can rise and lower as needed, there is no inherent issue with fiat currencies as long as the issuing party is reputable and wages increase at the same pace (up or down) with all prices