> If an IC takes on more and more IC work instead of management responsibilities, it's harder to promote them.
This is one reason it's critically important for a company to have paths for ICs to take on larger responsibilities that aren't necessarily management responsibilities. Not everyone wants to be a manager, and not everyone is good at being a manager. Some people want to become increasingly senior engineers. (They'll still, ultimately, be responsible for things that involve other people, but that doesn't mean they want to be a people-manager.)
This is one reason it's critically important for a company to have paths for ICs to take on larger responsibilities that aren't necessarily management responsibilities. Not everyone wants to be a manager, and not everyone is good at being a manager. Some people want to become increasingly senior engineers. (They'll still, ultimately, be responsible for things that involve other people, but that doesn't mean they want to be a people-manager.)