The real reason is the same reason that they have to close the matterhorn every year for refurbishment, and the same reason that they closed the rocket rods. The vibration of the cars passing throught the matterhorn shakes the structure so badly that it constantly needs repair. Budget does come into consideration as it would have cost a lot of extra money to engineer the ride in such a way as to not have the constant upkeep
That's not an excuse any more. They can detatch the two.