This doesn't even make conceptual sense. An author chooses to divert their working time to producing a piece of content (say, about a honey-guzzling bear) with the expectation that they'll be rewarded by the market for doing so, which is why they don't instead divert all their efforts into writing ad copy for PepsiCo.

The amount of reward the market provides is based on the value that can be extracted from that property. If value can only be extracted while the author draws breath, the market provides much less reward --- for the author, in this lifetime.

Bear in mind that intellectual property is in some ways even more defensible than real property. The rights to real property are fundamentally secured through conquest and forcible appropriation. IPR is generated de novo, from the creators themselves.

So, to me, the opposite argument seems to apply. There's no obvious moral reason that copyright should be in any way tied to the lifespan of the author. A cultural work is no less valuable because its author happens to get hit by a bus the week after they publish; why on earth should the market for those works be asked to consider that possibility?

(This is potentially an argument against creators, in the sense that an unusually long-lived author is no more entitled to excess rewards than an unlucky bus-strike victim is entitled to fewer rewards.)