We are living in an era of overcapacity. There is a huge difference between no monetary policy, conventional monetary policy and QE. There are huge levels of structural unemployment. Corporations like Apple pay 1.9% tax on billions of dollars of profit. The elites, both corporations and individuals, hide their money in tax havens while enjoying the benefits of the economies from which they have made their fortunes. This elite take over has been politically engineered.
Jobs have been shipped to China and through no fault of their own the lower middle class has seen its opportunities and wages diminished. QE supports financial assets which are disproportionately held by the elites. While as you point out this cannot be proven, in the long run I think the poor would have been better off had the Fed allowed the American economy to fall into a
depression. The “New Deal” and all kinds of financial reforms came about because of the great depression. But creating artificial demand of 1/15th of the economy when the gains from the economy are engineered to disproportionately fall to a
few, masks the underlying systemic imbalances.