Tangible property and intangibility - a metonymic property
"When property is SOLD, the owner does not still have it. When you SELL your creative works to the public via publication, copyright law allows you to continue to hold your property (for all practical purposes) for your entire lifetime plus 70 years."
There is a small precision to be made. "When property is SOLD, the owner does not still have it. " This is a quite precise statement. "When you SELL your creative works to the public via publication..." Sell" in this context is a metonym. Is a loose term used outside the field of law to denote other things not germane to the legal concept of selling. Like "selling the presidential candidate's image", what is something that is sold but not necessarily bought.
Selling is something that requires res, pretium et consensum, agreement and price, but most of all requires the existence of a thing - a certain and determinable thing, unique and equal to itself. Creative works (as Blackstone puts it) exists in contemplation, and lack the uniqueness plus self-equality properties.