Speaking of case study, Louis Gerstner's account of the turn-around is a great read [1]. I read when it was published, so not sure it has aged well; need to check it again someday.

[1] https://www.amazon.com/Who-Says-Elephants-Cant-Dance/dp/0060...

Even though IBM doesn't seems very sexy startup. But they survived 100+ years and trying to find way to stay in business.

They learn and adapt. They contribute significantly to Open Source. Now they are understanding importance of UI/UX design and trying to invest heavily on it.

Lot of big name startup even though succeed for short or medium term but struggling a lot in long run. I really enjoy reading the below book about IBM

Who Says Elephants Can't Dance? by Louis V., Jr. Gerstner (Outsider came to IBM as CEO) IBM is nearly in verge of collapse during early 90s. And he pulled it off.

http://www.amazon.com/Who-Says-Elephants-Cant-Dance/dp/00605...