Adds up to what exactly?you only buy a personal plate once...and it's with you for life so it goes with you from car to car, not just stuck onto the same car forever!
Mine for example means something to me and those who know me by name will instantly recognise it too - But it would mean jack all to anyone else, well except for that Canadian rapper who has the same name as me...
It still doesn't mean a firm should make millions of pounds of profit through it purely because they have the sole ability to do so.