This is true in many organisations where you are able to get promoted and work your way up the ladder.

When I worked in a bank, people would start out on the telephones doing sales or collections. The ones who were good on the phones were promoted to be senior associates or team leaders. They were good on the phones, not at managing a team. Next they get promoted to manager and head of department. It's crazy, just because they are good at one job, they get recognised by being promoted to the next level up. This continues until they are promoted to a level they are not good at and they don't get promoted any more.

In an engineering company, one of the design engineers was one of the best in the business, yet he got promoted so high that he was no longer doing what he was best at, he was running the department.  Why not make use of the highly skilled people in the job they are good at.

It's important to recognise this and work out where you want to get to in your career without being promoted to a position of incompetence.

As much as I believe in doing what makes you uncomfortable, it's not the same as becoming incompetent.