When Wall Street’s bankers see a problem brewing in the markets, what is their responsibility to clients and the financial system as a whole?

That’s the question at the heart of recent cases being investigated by the Financial Industry Regulatory Authority, or FINRA, as well as the focal point of the recent financial crisis itself. It’s also the issue at the center of the Securities and Exchange Commission’s fraud charges against Goldman Sachs, a lawsuit that the parties resolved earlier this month with the investment banking giant neither admitting nor denying any wrongdoing, but agreeing to fork over a record $550 million in fines and penalties.

The new attitude by regulators—a sea change from the previous deregulatory zeal and hands-off approach that many displayed at the height of the credit bubble—is that Wall Street has a responsibility to put a stop to subpar products reaching their investors. FINRA, for instance, accused Deutsche Bank Securities of selling mortgage securities to its clients and then failing to disclose the actual delinquency rates of the bad loans in those portfolios. (The bank, like Goldman Sachs, settled without admitting or denying the allegations and forked over $7.5 million to resolve the matter.) FINRA’s enforcement honchos have made it clear that this won’t be the last case they bring against the financial institutions who repackaged and sold mortgage securities to their clients.

That likely will make investors like Rob Kapito, president of BlackRock feel vindicated, even if it doesn’t appease them completely. In early 2009, in the immediate aftermath of the crisis that claimed the life of Lehman Brothers and forced a scramble for survival on the part of other large financial institutions, Kapito wondered aloud what would have happened had Wall Street institutions been able to sell to clients all the securities that were still on their books and that resulted in many of the massive write-downs. “Isn’t it ironic that the securities that they created are what took them down?” he questioned. “These were the securities that they wanted to sell to us, the buy-side institutions. Had they succeeded and sold them to us, wouldn’t they have been seen as the successful ones, and us as the fools?”

The reason that didn’t happen, Kapito claimed back in January 2009, is that BlackRock’s managers had a fiduciary duty to its clients of a kind that Wall Street firms didn’t possess with respect to their clients. Even without that legal duty, he argued that when he started in the business, “if we had created a security like some of these (mortgage-backed CDOs), we would have been fired. The senior people would have asked us, what is that, how does it work, does it work, and will people make money from it?”

Perhaps Kapito was looking back at the investment banking universe of the late 1970s and 1980s through rose-tinted spectacles. Certainly, by the time reporters began asking hard questions about Wall Street’s inability to “just say no” to marketing products that they could have or should have known contained more risk to their clients than they were disclosing, many of those bankers reacted to those queries with incomprehension rather than reasoned arguments. It wasn’t up to them to do the due diligence for their clients or to second-guess their clients’ risk tolerance or level of sophistication, ran the most commonly-heard response. If clients wanted above-average levels of return on their fixed-income portfolios in a low-interest-rate environment, the often-heard corollary went that the responsibility of the investment bank was to find a way to provide it.

One banker who provided a more thoughtful answer to that question was Ralph Schlosstein, the CEO of boutique investment bank Evercore. “In banking, we train people to react to a problem by finding a way to make money out of it,” Schlosstein explained. In other words, anyone who counts on a Wall Street firm to comprehensively analyze and disclose the full array of possible risks associated with the products which it plans to sell and from which it hopes to earn large fees, may be barking up the wrong tree. Investment bankers’ instincts aren’t to analyze problems and find a way of preventing them from growing, but to find a way to turn that problem to their financial advantage. Understand that and you understand why Goldman Sachs saw no problem with simultaneously selling packages of subprime-mortgage securities to its clients, while selling the same securities “short” itself, and ended up profiting while its clients lost money.

FINRA may well succeed in getting more of the firms it targets to settle allegations that they didn’t do what they could have done to avert the financial crisis, or at least blunt the impact on their clients of the securities they sold, especially given the post-crisis political and regulatory climate. But getting those financial institutions to admit that they should have acted differently is another matter altogether. Acknowledging that they could have done more and reaching a settlement to make allegations like this go away as rapidly as possible is one thing. Having them acknowledge that their entire modus operandi is flawed—that their responsibilities stretch beyond simply structuring products that they can sell and making money for their own shareholders—is likely to be impossible, at least for the time being.

And that’s why FINRA’s actions are likely to be of limited long-term utility. What the agency—and other regulators—can do now is to require some Wall Street firms to take at least some share of the responsibility for the crisis after the fact. That may provide a degree of satisfaction to those furious about the losses, the bailout and the rapid return to financial health of many Wall Street firms while Main Street continues to struggle. But forcing people to take responsibility after the fact is never as useful as devising ways to ensure that there is no crisis in the first place—that there are no sins of omission or commission for which a financial player needs to apologize.

We need to accept that while a tougher regulatory system is one ingredient in preventing future catastrophes, it’s not enough for that system to focus only on punishing past misdeeds. Nor will these external enforcement actions—regardless of the sum levied as a fine or penalty—be enough to truly transform Wall Street’s culture. As long as the collective response of individual bankers and traders and the firms they work for to a crisis that they see brewing is limited to finding a way to turn that crisis into an opportunity to generate a personal profit, regulators likely will find themselves concentrating more on punishment than prevention.

“There is such a thing as having good business principles, on making long-term strategic decisions about what business you’re going to do and with who you’re going to do business, and what kinds of business just aren’t worth the fees you get in the short-term,” a former Goldman Sachs banker recently told StreetWise.

Postmortems and punishments may make us feel better, but only that kind of attitude, when internalized on Wall Street and combined with effective oversight by regulators, can be counted on to prevent the events that culminated in September 2008 from repeating themselves as soon as memories fade.