Have you ever had a candidate that demonstrated the desired skills but didn't actually crack the case?
Experts - is cracking the case essential to passing a case study interview?
Out of all MBB companies, only Bain expects you to crack the case and get the final number in 70% of the cases. At McKinsey (especially with the interviewer-led cases) and BCG very often it's just about discussing various topics and demonstrating the right skills (Structured thinking, Business Judgement, Etc).
So don't worry too much about the final answer. However, always try to have a good pace, since you never know what the interviewer has in mind.
It is generally not required that the candidate "cracks" the case. This also varies widely by case, and interviewer. Some interviewers like to give very long, difficult cases, where completely solving it is very, very difficult, and the vast majority of candidates (including those who get offers) won't solve - this was the case with one of the partners I worked with at Bain.
Other interviewers will give more simple cases, and in this instance it is more of an expectation that the candidate with "solve" the case. In these cases, clients are more differentiated through the additional "gold dust" they provided in the case - for example, not just having a structured recommendation at the end, but going deeper by proposing next steps.
Finally, I am not sure what Vlad is basing his statement about "bain expects you to crack the case in 70% of cases". This is definitely not true, and I don't believe there is any specific expectation about candidates being able to come up with a specific answer.
Hope that helps!
Remember what the objective is: we want you to show that you can follow a structured (and MECE) approach, so that we know you will crack today's case, and the one tomorrow, and the one after.... if given enough time.
I can't speak to the percentages, but would agree the method is more important than the answer
PS: if you dont find the answer, it will hopefully be for lack of time, not for lack of creative ideas