The New York Times doesn't have subpoena power, but there are still a non-zero number of people in power who limit their shenanigans because they're terrified of ending up on the front page.
The government has a regulatory and investigative role, but it can't go out on a hunch or a rumor, a good journalist can (Which is not to say we need witch hunts).
One good journalistic organization can help keep a whole industry honest just by the threat of really investigating things that don't add up. WSJ is good at reporting, but I can't recall the last time they cracked a scandal in the financial world. Feel free to correct me.
Would a diligent, news-y CNBC have prevented the financial crisis? I doubt it. But perhaps they could've prevented or exposed some of the most ridiculous excess. It seems every person 'in the know' I've read has said that in hindsight they thought that Madoff was on the take, they just assumed he was an insider trader.
Would this stuff sell in comparison to Jim Cramer throwing pies? I don't know. But I have a hunch that a financial dateline style report exposing Madoff as a scam would've garnered a few viewers...