"Rich are getting richer while the poor remain poor" is not supported by the stated evidence of the growing income gap _ratio_. The ratio can increase even if the poor are becoming richer, so long as the rich are becoming richer faster.
I understood that statement to be talking about class mobility. Obviously 'poor' and 'rich' are relative terms, not necessarily pegged to a specific amount of income or wealth.
"Rich are getting richer while the poor remain poor" is not supported by the stated evidence of the growing income gap _ratio_. The ratio can increase even if the poor are becoming richer, so long as the rich are becoming richer faster.