I agree with you in general but a useful question to ask is: How easy is this to do outside of tech (and other competitive industries like finance)? Competitive industries have high upside but inherently have limited opportunities at the top.
You even see in this thread how people within tech but unable to pull FAANG salaries see this story as impossible. It's one viewpoint to think that it's possible for everyone to become skilled enough to work at a FAANG-like job (including passing the interview); probably correct so some degree. It's another (less rational) to think that every software engineer can work at FAANG-like jobs simultaneously; there just aren't enough positions.
This gets even more dire outside of tech. What job are you going to switch to every 3 years that nets you a 30% salary increase? If that kind of opportunity was wide-spread, there would be a lot less income inequality (or at least more social mobility).