If that was the sum of it, you'd expect to hear just as much bad stuff about Microsoft, Google, Apple, and so forth. That doesn't seem to be happening at the moment.

People also don't particularly want to read a story from a happy engineer at a big company either.

Additionally, the unhappy person who has an axe to grind is likely to go out of his way to publicize it, talk to reporters about it or write comments on the Internet about it. Happy employees are less likely to go out of their way to comment on the experience, and what they have to say is less notable on average.