There's a good podcast called Acquired. Highly recommend it. They're private equity guys who cover the history of companies and what made them great, and cover the topic very well.

For IBM and AT&T, from what I gather it seems like they missed out on multiple waves of new technologies because there wasn't a market for it, or the revenue was so low it wasn't worth their time. They were market maintainers, not makers. They also rested on the fact that they were the incumbents, so made the incorrect assumption that people would always default to them out of convenience.

Your second question basically falls back to whether FAANG make the same mistake; resting on their laurels while some small fry breaks into a market they deemed too small to serve.