If that is what really defines an L9 job at Google I think we'd all have been praising the typical L9 Google employees on HN long ago. And we'd all be justified in being angry Google decided to fire such a person.
Or maybe Google should pay their salary indefinitely because they were capable of disrupting a market at some point in their career? Or maybe yes, such a person needs to work at Google type company so all of us can benefit from the optimal situation from which to maximize their talent, even though such a company would let them go. Otherwise we'd all lose out on such a person being capable of contributing to the world if Google lays them off.
What else could they do then without a company who doesn't appreciate keeping them on?