Earlier quoted context omitted.
Case in point. Harry Markopolos is a fraud investigator who works for institutional investors "big dogs", not the SEC. He looked at Madoff's returns, the strategy they claimed they were using and took "4 hours" at home to figure out that it was fraud. Here is a choice section of Markopolos's testimony: http://www.youtube.com/watch?v=q1A7LdW0Y_s
Reading further, it may have more to do with corruption and/or apathy than inability. I doubt they couldn’t find first base in Fenway park, they simply didn’t want to go looking for trouble. https://en.wikipedia.org/wiki/Harry_Markopolos
That said, I just can't see how they could ever attract or develop the financial minds required to keep up with wall street.