PE puts very little of their own money into the deal though, while they own it they don't buy it. They use incredibly high leverage and often saddle the company with monstrous debt, then loot the assets to pay the interest and take management fees while doing all this. Red lobster is a great recent example. They sold off all the real estate, then had stores lease it back, turning profitable locations into losers. They often do the same thing with manufacturing, goodwill, brandnames and sales channels.

Think of this like an oil well. If you pump off all the gas, you depressurize the reservoir and can never get the oil. You need to slow your production to get the oil first, but private equity is happy to skim the cream and leave the milk to spoil.