"Those at the top" don't generally have that much cash. They have shares in companies, often ones they started themselves, which happen to be worth a large amount on paper. If you wanted to distribute that in a form people could actually spend (not just moving shares around) you would have to liquidate the companies those shares represent. In the process you would destroy far more wealth than you distributed and eliminate services and production capacity which were previously working for the benefit of the very people you're claiming to help.
People like to complain about public companies and their alleged focus on short-term gains, but that's exactly what this proposal represents: a short-lived and highly diffuse gain in short-term consumption for the masses at the expense of long-term capital investment and productivity.
