Really?
Perhaps KOTOR didn't sell as well as you thought considering that Battlefront quickly became the highest selling Star Wars game of all time.
However, before LucasArts was able to cash in on Battlefront they had released several duds in a row like Gladius, Super Bom-Bad Racing, Bounty Hunter, Clone Wars, Racer's Revenge, Flight of the Phoenix, etc. etc.
They also cancelled production on Sam and Max 2, and Full Throttle 2.