One thing happening right before another does not always mean that the first thing is the cause of the second. In this case you are saying that as soon as the U.S. left the gold standard completely real wages have declined. Sure, this is true - but leaving the gold standard is not the cause of the decline in real wages.
I could just as easily point towards the fact that until around '74 - in the 60's - America was the global superpower and as a result the employing class could afford regular wage increases to the working class and did so, primarily seeking labor peace (remember, the 60's were a time when labor was a powerful force in American politics and the U.S. essentially had no global competition). Due to increasing competition from emerging markets - globalization - U.S. profit margins dipped and in 1974-75 a deep recession hit. Workers wages were blamed(maybe even rightly in this case) and wages were scaled back. For an example, I point to the takebacks Chrysler imposed on autoworkers in 1979. Basically, that boom in wages was artificial... Something that U.S. businesses could afford then but primarily due to globalization cannot do now.
Oh and interesting factoid,
the M3 money supply of the U.S. has actually shrunk since 2008 despite QE1, QE2. which lends even more credence to my assertions that price increases in commodities lately has been supply/demand related and not so much about money supply(inflation!).