The biggest simplification that I disagree with in this post is that impact rises monotonically.
It's true that long-tenured engineers (if they're good) can do amazing things. Things that other engineers don't have the implicit knowledge or political capital to do. The problem is that once that project is over, it's not guaranteed that the next project will be as impactful.
So ... do you pay them for their impact? And promote them? Knowing you're guaranteed nothing the next quarter?
Or do you put up barriers to promotion? "Sustained performance" or "multiple successful projects?"
I'd love to see an approach to IC comp that's variable. Land a huge project; get a bonus. Everything past Senior Engineer is temporary; if you want to be paid like Senior Staff or Principal, do the work in that year. I suspect orgs could justify being more generous with bonuses because it's not recurring.
It's at odds to a lot of the way engineers look at comp, but it would align money with what individual businesses need in a more interesting way than the current "plan on your RSUs going up by 50% next year" comp plans at FAANG.