Also take this into consideration. THE COST FOR RENTING A STADIUM FOR AN EVENT. If Monster Jam moved out of vegas and went to somewhere like LA Coliseum or Olympic Park, it would probably cost a lot more than vegas to rent the place for the world finals. Think about it, those places have a larger seating capacity than vegas AND a bigger stadium track area than vegas.
Bigger seating capacity + Bigger track area = More Expensive Rent Cost
Even though those places are bigger than vegas, taking cost and everything else into consideration, FELD AS A BUSINESS probably wouldn't make as much money off of it as compared to vegas. Who knows, they could lose money rather than make it. Basically FELD is like any other business. They want to maximize their profits and want to be able to make the most money. If vegas has worked for them for 15 years, WHY MOVE??? If FELD did, they would be rolling the dice, hoping to get lucky, and pretty much risking maximizing business profits. I'm pretty sure that if FELD wants to be as successful as they are, they would continue to run the world finals at vegas and continue to build onto their success.
Believe me, this is coming from someone who is a member of the Board Of Directors of Special Olympics Washington. I know how businesses are ran.