"Because the fees charged by the mutual fund guys are fixed - it's a straight percentage of assets. Just like the fees charged by hedge funds which are taxed as ordinary income."

Taxable methodology isn't generally determined by the way you earn your income. The concept of long term capital gains was created to reward investors (those who invest their own capital) who hold capital in a given investment vehicle for over a year, not for whether or not they are taking on risk, or whether they are paid out based on a fixed fee or fixed percentage of profit. We don't tax waiters at a different rate for the money they get on tips (sweat equity) vs. their base salary.

Fees charged by private equity are also fixed - they are a fixed percentage of profit. So again, I don't see why this is any different. We have an investment vehicle taking in money, making investment decisions on the behalf of their investors and then making a percentage of the profits - all normal activities - nothing that warrants special tax treatment.

Comparing selling your company to carried interest isn't appropriate - apples and oranges - but to your entrepreneurs example: if they accept investment in their company, then their company has shares. Gains on those shares are treated exactly the same as any other share in any company - short term gains on stock held less than a year or long term if you've held it a year or longer. This is why many people exercise their options in a startup as a way to start that clock as soon as possible to avoid short-term tax consequences.

Again - PE firms are offering a service and will receive a good profit for their hard work. But that work often involves minimal capital on their part and therefore should not be treated as if it is their capital at risk.