The best way to look at any business is from the standpoint of the clients. So there are these certain basic things that aren't going to change. Companies are going to have needs for equity, debt, advice, FX, and derivatives. Individuals are going to have needs for auto loans, mortgages, something that looks like a deposit account, and the ability to send money to people. Those things aren't going to change.
However little of anything you have, you can always find someone who has less. Find that someone, and give to them from the abundance that is yours.