Apart from being able to draw fees and get a lower interest rate on the borrowed money, is there much of a conceptual difference between PE and a private investor buying a portfolio of shares on margin and reinvesting the unrealised gains or cashing out early whilst holding on longer term to his losers in the hope of a turnaround?

If there isn't much of a conceptual difference does the success or failure of the private investor vs private equity basically come down to the higher interest rate and the lack of fees?