If private equity buys a pharma company and cuts research, jacks up prices to extract money from insurance, that might be "clever" but it is not really benefitting anyone, quite the opposite.

Obviously a lot of capital is used to create more value, but it does so by using labour, so it is the creativity of the people working for that capital that is adding the value mostly, while the capital sits back and enjoys it's growth. This is the concept behind public traded companies.

I think it is more a case of the more access to capital they have. People who have demonstrated that they can create a lot of value usually get access to lots of capital, even if that capital is not theirs. It's pretty standard to not fund business ventures by one's self. An indication of a good business plan is buy-in from others.