"intellectual property" only exists because society collectively allows it to. it's not some inviolable law of nature. society (or the government that represents them) can revoke it or give it away.
Yes, that is why (most?) anarchists consider property that one is not occupying and using to be fiction, held up by the state. I believe this includes intellectual property as well.
A person being alive is not at all similar to the concept of intellectual property existing. The former is a natural phenomenon, the latter is a social construct.