"I was 24 years old, with no experience of, or particular interest in, guessing which stocks and bonds would rise and which would fall."
So do many MBAs, and yet they are hired to do the job. One does not have to learn by the seat of one's own pants.
The man also describes Wall Street of 1985. There was a revolution in finance, to which he appears oblivious, since mid 1990s. The qualifications in present-day banks are incomparably higher.
Like the author, I was very much appalled at the extent to which finance lacked rigor. But that was the state of the art, and those who knew litte were giving advice to those that knew even less. That is how it always was, in all areas, and how it should be. Just look at the doctors in 1900s: it's amazing how little they knew. Were they frauds? Of course not: however little they knew, their patients knew even less and needed help. Doctors did their best. So do bankers.
You must like the link because it seems to confirm what you WANT to be confirmed -- your unfounded beliefs about Wall Street. It has little to do with reality however, and written by a man who obviously cannot see the forest for the trees.