"So what - it's still no excuse for theft. I'd like a Rolls Royce, shall I just go steal one?"
No, he is saying he CAN afford the Rolls Royce - he wants to give them his money, its just that unnecessary artificial restrictions have been put in place to make the purchase difficult, or not possible.
He can COPY the Rolls Royce perfectly by building his own - that is an infringement of their design. He didn't steal the car and as such did not deprive the dealership of a physical item at their cost - i.e. Theft. It may however have cost them a sale - which was by their doing anyway since they refused to sell him one in the first place!
I don't there is any mental deficiency with the OP - just a lack of understanding on your part?