Ehhh, my mentor worked at McKinsey and often times they’re brought in to make a decision the C-Suite already had on their mind but needed justification to act on.
Example, CEO John Smith at F500 company X wants to offshore his US based call center. He’ll call McKinsey in to ask what are some ways the company can go about reducing costs within its call centers. From the get go the CEO has framed the the case and intended business solution.
Long story short, people overplay how much McKinsey’s influence is on things like layoffs, outsourcing etc. Often times those decisions are already made but McKinsey will provide the analysis and pretty ppt slides to justify the action.