NEW YORK (MarketWatch) -- Wall Street, in shaping corporate America, has become just like it.

Brokerages and banks are bought and sold. Thousands of jobs are created and lost in every turn of a cycle that's spinning ever faster. Firms have lost their character and style. They have become indistinguishable. They sell commodity services. Everyone does initial public offerings, syndicated loans and bonds, and they all provide strategic advice to corporations.

In a rush to do everything, most Wall Street firms aren't known for anything.

It wasn't always such a grind. The Street used to be a place where relationships mattered, the rise and fall of markets were less dramatic, and company cultures were as colorful as the ethnic neighborhoods of New York.

There were the rowdy guys at Salomon Brothers, the bond guys at Lehman Brothers, the rough-and-tumble Bear Stearns Cos. bankers, the Catholics at Merrill Lynch & Co. MER, +27.69% , the WASPs at J.P. Morgan & Co. JPM, -0.84% and the elitists at Lazard Freres.

There was a dark side to all of this, too. Women and minorities were scarce. If they did manage to cross the threshold, they were treated with contempt. Finance was an old boys' business, and highballs and cigars were their calling cards. Wall Street was exclusive, but not in the way it's exclusive today.

Imagine people like Dick Grasso and Jimmy Cayne, neither of whom finished college, or Stanley O'Neal, who rose up from the floor of an auto plant, making it on today's Wall Street.

Instead, the top jobs are now held by people such as Citigroup Inc. Chief Executive Vikram Pandit, who attended private schools in Mumbai and then earned a doctorate in finance at Columbia University, or J.P. Morgan chief Jamie Dimon, who went to the exclusive Browning School in New York and Harvard Business School.

They are smart guys, and, while Pandit hasn't been on the job too long, Dimon is a proven leader with the confidence of his troops. They are more than capable as executives. But they are also job-hopping mercenaries.

Both have worked at multiple firms. Some might say moving around is good because it gives a leader a more complete worldview. They are also considered more objective and less likely to spare sacred cows.

A skeptic might argue that Dimon, Pandit and Morgan Stanley's MS, -2.35% John Mack diminish the existing culture of a firm and send a signal to the rank and file that there's no use in staying loyal to the company.

Thainisizing Merrill

No executive embodies this new kind of financial world than John Thain. The CEO of Merrill Lynch, Thain, 53, is at his this third major Wall Street firm in five years. Expected to follow Henry Paulson as chairman and chief executive of Goldman Sachs Group Inc. GS, -1.14% in 2003, Thain instead bolted for the New York Stock Exchange.

Less than four years later, Thain left behind NYSE Euronext NYX, a global and publicly owned conglomerate of markets. He eliminated remnants of the not-for-profit exchange: the dining room, the shoe shine, the in-house barber. He threw out tradition in favor of economic efficiency and pitted the NYSE against its archrival, Nasdaq Stock Market Inc. NDAQ, -3.18% , in a race for market share across the globe.

In short, he made stock markets another commodity.

Today, Thain is shaking up Merrill Lynch. He's cut jobs and undercut shareholders through capital raising. Thain is considering the sale of Merrill's stakes in BlackRock Inc. BLK, -0.68% and Bloomberg L.P. These were sacred cows even for Thain's predecessor, O'Neal, who was accused of destroying Merrill's culture by slashing jobs and streamlining the company.

Contrast Thain and O'Neal with David Komansky, who graduated from the University of Miami, joined Merrill as a broker in 1968 and rose to CEO in 1997. He was shown the door in July 2001. A couple of years later, O'Neal remarked: "I think clubs have their place, but not in modern commerce."

Partners to public

Thain and O'Neal aren't the first of their ilk, and they won't be the last. Guys like Cayne, Richard Fuld at Lehman Brothers Holdings Inc. LEH, and, to some degree, Charles Prince at Citigroup C, -2.12% are the last of an old guard of top managers who rose through the company and ran each division to gain experience. The idea was that each particular company did business in a certain way.

Now, companies all do business the same way, and your education at X firm is good at Y.

In the mid-1980s, Wall Street began a slow evolution into the bland mess it is today. Partnerships dissolved into public companies. Bear Stearns went public in 1985, Morgan Stanley in 1986. Lehman had its IPO in 1993. Those were bad enough, but when Goldman Sachs went public in 1999 and Lazard Ltd. LAZ, +1.59% finally succumbed in 2005, the industry's biggest names had all become subject to the whims of shareholders.

Combined with the mergers that created the big banks and brokerages, Wall Street has taken its own medicine. Those culture clashes we used to hear so much about -- the kind that were supposedly going to derail Credit Suisse's acquisition of Donaldson Lufkin & Jenrette -- are an afterthought these days.

These new firms may be leaner and meaner. They may be more nimble. They may be better positioned to compete with the rising financial powers overseas. Big investment banks have done unto themselves what they've done to the rest of corporate America: made it sterile.

The new Wall Street isn't a bad place, but you might not recognize it.

It all looks the same.