The SEC could certainly do (much) more, but I'm merely claiming that they seem to be improving. Most of the articles I've read about Mary Schapiro's recent retirement conclude that she left the SEC in a better state than she found it. For example, from [1]:
She inherited a mess at the S.E.C. Critics contended that Christopher Cox, her predecessor, left an agency with low morale that was ill-prepared to cope with the financial crisis... Ms. Schapiro directed much of her early attention on the beleaguered enforcement unit... Over the last two years, the unit has filed a record number of actions and brought 129 cases against people and firms tied to the crisis.
She inherited a mess at the S.E.C. Critics contended that Christopher Cox, her predecessor, left an agency with low morale that was ill-prepared to cope with the financial crisis... Ms. Schapiro directed much of her early attention on the beleaguered enforcement unit... Over the last two years, the unit has filed a record number of actions and brought 129 cases against people and firms tied to the crisis.
[1] http://dealbook.nytimes.com/2012/11/26/schapiro-head-of-s-e-...