Lost in the angst about income inequality is the fundamental point that the poor’s purchasing power is increasing all the time. Innovation is the chief explanation, as I lay out in my latest column for the ROB’s Economy Lab feature in the Globe. I am one of those people who thinks that the gap between the most and the least well-off is far less interesting than whether we are improving the lot of people at the bottom. One of the most effective ways to do that is to increase their purchasing power, which private sector innovation does more effectively and effortlessly than increases in government transfers.