There is a flip side to this, as some (many? most?) excellent ICs either become poor managers, or hate the job of dealing with humans, or (frequently) both. This is well known and many companies actually want and support top ICs who want to stay ICs with significant freedom to choose projects, generous (time, travel and $$) conference budgets and other perks.
Thus at least some ICs do not go anywhere after they peak (hopefully plateau), which can be a good place to be. But sooner or later they will likely be working under one of their team members whom they did not think much about (who may just be better with people than with technology). This is not a reason to lose any sleep; just something to keep in mind. My 2c.