You may be right.
I thought it was a great honour to be awarded a Nobel Peace Prize until President Obama got it for doing nothing except not being President Bush. It sullied the Award and was at odds with the true spirit of the award.
That being said, if someone has worked hard in any of the Nobel categories, and is nominated and even awarded one, then I think they should accept the honour regardless of who they are.
Politicians get awards for achieving something in a relatively short period of time (the above mentioned President notwithstanding) whereas those nominated in the other fields seem to be nominated for a lifetime achievement or for body of work done over decades. Prince Charles work would fit that model.