Stock returns average about 5% above inflation. Invested conservatively (there are rules about that, how to spread your risk, but nowadays you can just buy Index Funds), that means you can take 5% per year out for living expenses.

Of course, if the market goes down, your income goes down. If it goes up more than inflation, you can give yourself a raise. There's no way to eliminate all risk, but this is relatively safe.

Banks don't make stuff. They lend money to people and companies. A loan to make stuff has to pay less than the company is making. That means that the loans the bank makes with your money have to earn less than the companies are making. You keep your money in the bank because it pays better than keeping it in a sock, but other than that it's for convenience, not return.