The result is a downward spiral. Wages have been stagnant in America for more than a generation. People jump on the sharing economy bandwagon not just because they can, but also because they have to. It makes me sad, but I know that personally -- in a two-paycut household, with two kids on college at the same time -- I haven't bought any recorded music, even on iTunes, in at least a year. It would be kind of cruel telling one child to drop out so I can download the new Foxygen, so the choice is to stare quietly at the lights of West Philly from a speeding El or listen to Spotify -- and you can guess which I choose. But this all creates a downward spiral. Putting less money into the economy means fewer wages and more layoffs, which only pressures people to find new ways to share. I wonder how many UberX drivers and Airbnb hosts are laid off journalists or travel agents, trying to survive. Just today, a business writer wonders how to measure the gross national product as actual spending disappears -- thanks to services like Uber.