Intellect, theory, risk taking and reality

From the outside, trading opportunities within the big financial institutions or investment banks seem to be a closed shop. I took a look at job opportunities in the City of London this morning and all of them seemed to want people who were educated to a degree level, and/or who already worked in a financial institution. This obviously rules out bozo's like me, who left school and didn't proceed into further education, or who have never worked within the industry.