In my opinion the only moral justification for having an intellectual property rights is so that an individual or an organization (lets call them the innovator) can benefit from their hard work or effort of discovering a new knowledge or invention. But there must be a limitation because in reality every new knowledge can be discovered by just about anyone, the innovator just happen to be the first so they cannot say it's theirs. So in my opinion there should be an expiration to having an intellectual property rights. After the innovator has benefitted enough from their new knowledge or invention then it must already be shared or used by anyone. After all, that new knowledge they have will eventually get discovered by someone else.