Back when Ash first headed to Misty's Gym, her sisters were shown to be incompetent...at first. The next time they appeared, a few Pokemon in there were evolved. They seemed to be perfectly capable of taking care of the gym without Misty, and each time we heard more about them, it was about how great they were (one COTD (Dorian) even admitted they were hard to beat. Then in Gotta Catch Ya Later, they suddenly go on a vacation, leaving Misty stuck there forever, and in Chronicles, they were suddenly completely incompetent.
How did they go from that...to this?