For some time, I've suspected that zero interest rates for banks, i.e. the wealthy, contributes to inequality. I have no idea how to prove such a hypothesis. (Which makes it the same as every other economic theory, no?)
This reasoning has always sounded suspiciously like trickle-down to me. Give cuts to the wealthy (banks), and it'll 'trickle down' to the average consumer. Yes, consumer interest rates are lower...but only because the wealthy's rates are nonexistent.