I saw it first hand. My manager was pushing everyone to get promoted to level 5, of the few who didn't, one was put on a pip then fired, the others worked like madmen after seeing that, still didn't get promoted and somehow moved into another group. They still haven't gotten promoted but they work insanely hard/ aren't the same people. I guess it depends on the group, but I was told that timelines for promotion to level 5 are an unwritten rule.
At Google, if you don't make it to level 5 sweng within a certain amount of time(2 years from being hired at level 4), you will most likely get fired. After that you can relax more. So the fluff in software engineering(including managers) is minimal. Facebook though... Ask their employees how that build system is working out for them. There's a lot of doing, agreed, but sometimes you need to just take a chill pill, stop the goddamn hacking for chrissakes, design THEN code.