Thoughts on my MBB interview process

Apologies for the long post below but wanted to get people's thoughts on my MBB interview process.

I've been working in a different industry for a few years applied for a BA/AC/A role but after almost 9 months and going all the way to final round, it was decided I wouldn't get an offer.

The usual two rounds of two case interviews was broken down into four separate interviews, on separate days and sometimes months in-between. After being told I had passed the first round, I was only provided with very brief feedback on my behavioural question response. I asked if there was feedback on my case performance and was told this would not be provided.

After my final round interview on Friday afternoon, I was told by the partner I should expect a call the following Monday with their decision. Call didn't come and I waited another week before reaching out to recruitment but still no answer. About three weeks into waiting I tried to schedule a call with HR to give them an update on my life situation as I was planning on relocating, regardless of the outcome.

The HR call turned into a no-offer call, delivered by HR. Feedback was I was not MECE enough (more the CE side), even in the first round and I didn't talk enough about the context of numbers. The latter I was taken back by given it's all I do in my current role.

Having shared this story with a friend, he told me someone he knew had just received their offer call after waiting close to 6 months from the same firm.

I'm not sure what to make of it all as it's so different to what I've read the experience to be.
Whether I never really had a chance at getting the role to begin with (and was used as a benchmarking exercise?), they are holding back offers to create a pool of quarantined headcount they can draw upon or I simply rocked the boat too much by wanting them to get back to me ASAP.