The gurus, though, may be overestimating the return required of private equity for both its illiquidity and risk. There are benefits to having a fund manage your investment, and private equity is quite a capable manager. During the financial crisis many of these funds were able to salvage near bankrupt investments and turn them into profits.

Take Calpers again. Much has been made of the fact that the fund’s private equity investments have not exceeded its benchmark in recent years, although they have done so over a 20-year period. But the benchmark itself may be at fault. It is an amalgamation of domestic and foreign stock market indexes with a random number — 3 percent — tacked on. Whether this benchmark captures the risk and steady return potential of private equity seems unclear. Calpers is re-evaluating this benchmark and will probably change it.

Even with all of these caveats, there is no doubt that the private equity asset class has been a savior for many pension funds and endowments. Small pension funds (a billion dollars or less) still beg to get into larger private equity funds and are regularly turned down. It is only a lucky few that get access to the right private equity firms.

The fact that private equity has performed so well over the decades also puts the recent Securities and Exchange Commission investigations into private equity fees into perspective. In June, the regulator accused Kohlberg Kravis of improperly assigning more than $17 million in expenses from “broken deals,” or unsuccessful buyouts, to investors but not to co-investors that included executives of the firm. Kohlberg Kravis agreed to pay nearly $30 million to settle the charges, an amount that included a $10 million penalty. Over a six-year period, the firm had $338 million in expenses from deals that did not succeed.

The S.E.C. has also gone after firms like Blackstone (a $39 million settlement) and Fenway Partners (a $10.2 million settlement) over their fee practices.

It is hard to gauge how important all this is. These companies ought not to be engaging in these practices. But these are small amounts amid the billions of dollars of fees. One also has to wonder where the investors are. These are all sophisticated investors who can ask about and deal with these fees. Was there a practice that investors didn’t know about?

More important, a key ingredient of private equity’s success is that it can earn those returns and take its share of the profit. If private equity’s profits are narrowed, the question is whether returns will also be reduced. Perhaps not, but one suspects that private equity firms will simply increase their normal fees to compensate.

And so, in the debate about private equity perhaps we should balance the criticism of private equity firms for excessive fees with the great demand for private equity investments and the important role they play in meeting investors’ and pensioners’ needs. It brings to mind a line from when private equity first became prominent in the 1980s: Where’s the beef? The answer is, it’s with those stellar returns.