Excellent thread, very impressed by many thoughtful responses below. I would add this is the classic 'piece of the pie' video, this is go-to stuff for liberal/progressive arguments against free enterprise, against people like Ron Paul. This is the truly dangerous stuff because it is so effective in swaying the independents and independents decide elections. So tell your independent friends that this video doesn't say the poor and middle class have sharply lower standards of livings, i.e. they once had washing machines and now we're back to washboards, no.
What it also doesn't show unless you know what the numbers mean is that the pie itself grew at an incredible pace because of the risk-taking and ingenuity of capitalists in America's first 195 years and since about 1971 it has continued to expand through phony growth that won't last, through reckless monetary and fiscal policies.
The real enemy of poor and middle class prosperity has been stated elsewhere in the thread, economic interventionism and the inflation it brings.
Speak for yourself.