Often, I don't think you hire McKinsey to solve your problems - you hire them when your problems are already out of control and you need to deflect the blame. They give it their best shot, if they turn it around then they're heroes, if not, you can blame them and they still get paid.
(1) Partners would gladly communicate that back—the payoff to keeping one gig on track is far less valuable than avoiding public scrutiny
(2) If they did ask to move the goalposts, I suspect the city would have been amenable
Doubling down to bet on moonshots is not McKinsey’s MO. What are managing consultants good for? Starbucks on two corners of the intersection, breakfast menu at your favorite fast food eatery, and many (MANY) restructuring plans (rightsizing initiatives, aka RIFs)
Heads we gain credit for giving you an amazing strategy, tails you lose because you don't know how to implement our amazing strategy.
It's a Heads I Win Tails You Lose situation.
But it's surprising how lucrative it can be to set yourself up as a Roulette Coach.
That said, I'm sure they gave upper management some validation that we weren't just drinking our own Koolaid. And they gave business planning staff a fancy spreadsheet model to play with--which helped keep said staff out of our hair.
Ultimately, the product was fairly successful although the company couldn't really overcome a bad strategic position.
It's the classic can't-be-wrong-no-matter-what-happens situation. Since there is no practical way to re-run the experiment, they can always claim "at least we made it less bad." And the clients are prone to buy into it also, because it makes them look like they didn't make a bad decision to engage the consultants.
Same thing frequently seen with politicians and their supporters.
Simply put, they are aware of their biases, they try and adjust contractually to align, they have smart people (because they can afford to be picky) who have a tremendous work ethic. Just don’t let them anywhere near Swiss Airways! [1]
[1] https://tbkconsult.com/did-mckinsey-company-kill-swissair/