After a tough 2008 and 2009, Wall Street and big companies made a strong comeback in 2010. By conventional wisdom, that is a harbinger of a broad, strong recovery. But these are strange times, and we may be seeing the economy of the super-rich finally decoupling from the rest of us.

There is no arguing the boom on Wall Street. The five biggest New York banks set aside $90 billion for year-end bonuses, and bidding wars for spacious next-summer Hampton rentals are hitting $400,000 for the season.

Corporate profits are breaking records. Companies’ third-quarter earnings were $1.66 trillion. Awash in cash, with little to spend it on, they are raising dividends, buying back stock, and looking for acquisitions. All of that further fattens Wall Street’s bottom line.

Caterpillar, or “Big Yellow,” the brawny Peoria machine maker, is a good example. It is a flagship American company, where executives routinely wear American-flag lapel pins. Cat had a tough couple of years, but has recovered brilliantly. For the first nine months of 2010, sales were up about 20 percent, and its profits have nearly tripled.

Now look behind the numbers. Sixty-nine percent of Cat’s sales last year were overseas. Sales are especially booming in Asia and other emerging markets, where they have plenty of dollars and a desperate need for more highways, tunnels, and big sewer systems. Cat does not go into detail about how its products are sourced. But a clue is that half its plant and equipment is also overseas, and the percentage is growing.

There are probably still some very large pieces of equipment that are made only in Peoria, but if Cat is like other big companies, most of what it sells is put together as close to the market as possible. So Cat’s success will have little impact on heartland employment. High profits may ease the hiring reins a little, but the big job bumps will follow the sales.

Cat is a model of the successful American company. We are very good at making the high-end gear that is at the top of most global shopping lists. We excel at big-ticket construction equipment, drilling platforms, airplanes, giant engines, chemical plants. But in the absence of a massive stimulus program to, say, rebuild the American electric-power grid (fat chance!), the customers for those products will not be in America, and neither will the jobs.

The Federal Reserve has been trying to spur the economy by holding interest rates at historic lows. One perverse result has been the emergence of a massive dollar “carry trade.” Big investors, like hedge funds and private-equity funds, borrow dollars in the United States at extremely low rates and invest them in fast-growing emerging markets overseas at boffo returns.

Low interest rates have also triggered a spate of profit-taking at private-equity funds. These are partnerships that purchase solid companies, usually with large amounts of debt, in the hope of taking them public again at a high profit. But now they are extracting profits the easy way. They borrow a billion or so on behalf of one of their portfolio companies and pay it to themselves as a “special dividend.” The company ends up with a lot more debt, which may later require job cuts.

There have been a few wisps of an incipient economic recovery—a tiny uptick in private-sector hiring, better-than-expected early Christmas-shopping results—but they are still tiny. The big shifts in activity have all favored the biggest players, the ones who can sequester acres of money to swing into Brazil, or commodities, or for a grand takeover. That is why Wall Street is wreathed with smiles. The scary thing is that they might be able to stay fat and happy while the rest of America molders in the doldrums.

Former White House Chief of Staff Rahm Emanuel famously said that you should never waste a good crisis. If the effect of this recovery is merely to lock in the position of the top 1 percent, and speed the impoverishment of the middle classes, it will indeed have been a wasted crisis.

Related: The Wall Street Meltdown, by John W. Weiser