Excessive regulation over many decades culminating in the coup-de-grace -- the Dodd-Frank legislation has destroyed the bank business model.
Note the stock price collapse of the big money-center banks that is currently in progress. Commercial lending, trading, prime brokerage, and market making are businesses destined to disappear in a sea of red ink. The new army of compliance officers -- the only part of commercial and investment banking that is growing -- has to be paid. That doesn't leave much left for bank profitability.
So, what will the banks do? We are already seeing what they will do. They are moving to the "fee" business model, charging for bank transactions -- check writing, transfer, wires, and so forth. That model won't work. Bank overhead is far too high. So, the banks are rushing to expand wealth management which, thus far, has not been made illegal by regulators. But, even wealth management will fall victim to the regulators' hatchets in time.
Take a good long look at your commercial and/or investment bank. It will be unrecognizable in a few years. As for profitability, just take a look at how their stock prices are faring so far in 2016.