Why do they have clauses to prevent you from selling? It's a prize and up to you to do what you want with it surely :)
Because as a new owner the selling value of the new car completes directly with the current retail value of the same new car and so having the same selling price means that you would actually get more $$ than the dealers and the car company. It would be still selling at new car price and not depreciated as you are likely to be the only one or the few people in the country with the latest car model. Its a clause to prevent over inflating car prices etc etc.