Is inheritance justified?

Yesterday I went to Mannington Hall, the residence of Robin Walpole in North Norfolk. He had a allowed it to be open to the public for charity. It is a house that has been in his family for some three or four hundred years. he got it be being born!

Earlier in the week that was a discussion on the radio about why the famous speech by Martin Luther King was heard so rarely. The copywright is owned by the Martin Luther King Foundation and the charge for its use. Now copywright on books, music etc all tend to be lost about 40 years after the death of the originator.

I was speculating, what is the difference.  Compare Mr Walpole and some descendant of Charles Dickens, they can make no use of the books that Charles Dickens wrote but Mr Walpole still gas access to all the properties his ancestor bought all those years ago.

Should intellectual property be considered any differently? It might apply to patent as well. if a company has a patent it expires after a certain number of years but if it owns a coal mine it lasts forever.

Is this a historical anomaly, remember the laws were developed by the land owners to protect their own interests and that still seems to be a fundamental attitude in English law. Is it time for a radical rethink