OK, from a pure hedonistic view - let's say at some time in the future, there are no more humans left. Why would it make sense to invest anything into economic gain in the time before that happens? You'd rather run the economy into the ground to extract as much value as you could from it, before the end of human existence. You - or else someone else who is the last human alive - are "leaving something on the table", so to speak. Otherwise they are just leaving value around for wildlife.

In other words there would be a time, maybe dependent on the rate at which remaining humans can unwind the human economy, past which any effort at collective economic gain wouldn't be worth it.