It's rare that there are actually anywhere near as many roles at the top of the IC pyramid as there are in the people management track, by usually 3x or more.
If you want to get promoted to a higher level as an IC, you can compete for one of the maybe 3-5 staff+ spots available from the, say, 50 engineers around you. It's even rarer once you get above staff engineer, to the degree that it's disingenuous when most companies have a career ladder with those positions on it.
Or, you can shift to management, and have access to positions that might be as many as 10-15 per 50 engineers if you include middle and upper management. There never seems to be a cap on the number of vice presidents at a larger company.
It's unrealistic to just say "Oh continue to be an IC, do good work and take on more responsibility and you'll get a staff position", because there simply aren't the jobs available at most companies for staff, senior staff, or principal engineers. Also, it's often challenging to change companies when you're in those roles - you can't just pop down the street because a significant majority of companies just don't hire those roles externally very often. Contrast with management where being a director of engineering at company A often gives you a solid option on company B or a senior director role at company C.