My friend did skip flights many years ago, he said it was due to competition. You have three airports A, B, and C. Airline X has flights to B but most don't.

My friend did skip flights many years ago, he said it was due to competition. You have three airports A, B, and C. Airline X has flights to B but most don't. For arbitrary reasons the flight from A to C stops at B. When pricing tickets flights to B can be more expensive due to lack of competition from other airlines flying into B. However flights between A and C (which is a popular flight) have to compete against other flights since it is a popular route. Thus you end up with an expensive midway but a cheap overall ticket.