Just understand that CBs only influence the demand side of the economy- ie how easy/ cheap it is to get money. If the crisis is supply side, all they can do is constrain money supply so people can’t afford the scarce resources anymore.
The interest rate is the return on capital as much as it is the cost. They are two sides of the same coin. Which is why persistent low interest rates are bad: money may be 'cheap' but the return on capital is low.
