Actually, Wall Street isn't the reason most of us have jobs. First let's clarify terms. A bank takes in money (your savings) and lends it out to people/companies. Investment firms deal with stocks, bonds, derivatives, and all that. Sure, banks are a crucial part of the economy, but there's a reason banks and investment firms were separated by law for so long. When investment firms inevitably fail, you don't want them to take your banks with them.
When people talk about Wall Street, they're not talking about the basic financial structures that are low-risk, comprehensible, and low-profit. They're talking about the high-risk, high-profit things (derivatives of derivatives of derivatives, balloon loans, no down payment mortgages, uncapitalized equity insurance, and suchlike) that even those playing with them didn't understand. They're talking about hedge fund and equity firms that literally destroyed the economy and paid no price, and the people who were at the head of them didn't pay anything either. They're talking about growing inequality- bonuses of several million dollars paid to CEOs at failing firms while workers are laid off and unions forced to renegotiate contracts. They're talking about how the Walton family alone owns more wealth than the bottom 40% of Americans combined. They're talking about wage deflation- in real terms, ie accounting for inflation, the average American worker earns less than s/he did in 1970. They're talking about how Mitt Romney, a scion of Wall Street, mentioned $250,000 per year as a middle class salary when the median income in the US is closer to $50,000 and has actually dropped over 7% since 2009 (http://www.deptofnumbers.com/income/us/
And actually, minimum wage IS supposed to be for grown people. It was originally introduced because companies, who hold almost all the bargaining power when hiring employees, weren't paying people enough to live on. That's horrible for the economy, because people who are underfed, underclothed, and underhoused are not as productive and don't spend as much, which means there's less monetary circulation, which is what makes the economy work. Corporations pay as little as possible on anything, because their job is to make as much profit as possible. Things like minimum wage, safety regulations, pollution controls, overtime laws, child labor laws, and other regulations are supposed to prevent corporations from exploiting their workers. In the US, we do an OK job at it. The least unionized, least-oversighted industries are also the ones with the lowest wages and worst working conditions. This is not a coincidence.