The classic playbook includes making a lot of debt, and then leaving the lenders holding the bag when the company files for bankruptcy. It can only be considered efficient if con artistry is efficient, that is, efficient at taking the money from the hands of people who trust other people "too much".
This is over simplistic and if everyone knew this is what happens when PE comes into play then no one would lend to PE-backed companies. Often times these debts can work out.