Boom times created by basic human nature (ie. conservative principles) are a tough time for liberal and progressive thinkers due to the bountiful evidence of their previous, and unfortunately future, failures.
In these times they resort to many creative arguments which carry a significantly higher emotional appeal than rational. Among the most popular is the observation of the income gap, or wealth gap or nom du jour.
I am not fooled by this statistical trick for the simple reason that the bottom is a fixed point. The ‘poor’ will always be at or close to 0 while the ‘rich’ will be valued at an ever-increasing numerical value.
Even in a slow-growth economy, the normal inflationary trend of the currency will cause a larger gap without translating to any real increase in purchasing power.
What the liberals and progressives will never point out is that during past expansions, the vast majority of people moved up on the scale and away from 0, but conveniently for their contrived argument, 0 remains 0.