Hand-out motors will only create an illusion of parity, assuming all the motors have been verified as equal. They can't equalize setup, driver ability, and all the other variables involved in this hobby. They also can't fix poor sportsmanship, bad marshaling, meek race directors, inadequate tech, etc.
I do agree that in some classes at specific big events, a hand-out motor might be a good thing. But I don't think racers should ever have to pay for a hand-out motor. The motor manufacture should be more than willing to provide their motors at no cost as a normal cost of marketing and/or research and develop. At a minimum it could be an opportunity for a manufacturer to show how good their product is for the hobby and possible club racing. Imagine the headline saying how close the racing was at a big event because XYZ's motors were so good (in a specific class). But unfortunately that won't happen because many of the manufacturers know how to use our insecurities to get us to spend more money on the "motor of the moment".
The reality is that anyone willing to participate/travel to a large event knows that racing isn't 100% fair. The best thing any race organizer can do is be informed about the things that might be creating an unfair advantage and implement rules to lessen/eliminate any advantages (up to not allowing specific equipment).
In the end, I would much rather race at an event with strict tech/race director knowing that even the best racers will be disqualified for minor infractions than at an event that makes me pay more money to use a hand-out motor.