Since 2009 the Federal Reserve and other global north central banks have, first hesitantly and enthusiastically, been trying to sacrifice the health of the commercial banking sector in order to keep the life support machines that are keeping the rest of the economy alive going.
Your average commercial bank needs a 2.5% margin on its liabilities in order to cover the cost of its branches and its ATM network. Commercial banks are used to taking their deposits, sticking them in long term Treasuries and similar assets, and relying on time, diversification, the slope of the yield curve ,and the normal level of interest rates to generate the revenue so that they can earn profits if they manage their branches and ATM networks efficiently. Since 2008 that has not been a profitable strategy for commercial banks. Thus commercial banks have been under enormous pressure for a near-decade now.
It is there, I think, that central banks have been inflicting significant pain. It is not the case that extremely low interest rates on extremely safe assets has been keeping alive businesses that ought to shut down. For small businesses, credit is tight. Equity earnings yields are about normal–a company that is trying to think about whether to expand or payout its earnings is not facing any sort of environment in which there is a cost of capital that is in any sense “artificially low”.
So I do not see the Fed as having given any sort of pass to industry as a whole at all. It has kept the rest of the economy functioning while imposing very heavy pressures on the commercial banking sector. This is not normal. But it is not a bubble…