I think it doesn’t really need much explaining anyway. Just from their example, 2/3 of those tasks (keeping the fire going and protecting from predators) required just… being awake and reasonably alert. I mean you could spend the time sitting around the fire making arrows (or spears or whatever, not sure what they had in year 40k BC), but maybe they ran out of nice stones to sharpen.
Probably most of us would not want to trade places with a substance hunter/gatherer, but their lives had downtime, right? I would expect their lives to be punctuated by good downtime (got enough food to eat and a good supply of tools, time to relax) as well as bad downtime (wasn’t successful at hunting or gathering, ran out of resources to process).
You are deceived by the propaganda that was largely pushed to promote and rationalize industrial age interests and exploit industrial labor camp factory inmates. Even above people have said things like “no one would want to trade with a subsistence life”, which is based on the assumption that their life of being a wage and/or debt slave or slaver of the system is a superior state of being. Merely historical artifacts we have found and what we can plausibly piece together tell us that at least people’s lives had meaning and were authentic, which most people today in the West simply cannot say with any sincerity.
Are you better off because you can play video games and doom scroll while stuffing yourself with people shop chemicals and then take lizard toxin to control your diabetes and lose weight without doing anything while you have approaching zero authentic human connection, let alone culture not astroturfed by some corporate profit maximizing creative studio?
At least if you’re doing light farming and harvesting and’s spending all your day with your people practicing your cultural traditions passed down through the eons, you’re actually human, not whatever this is in the west today that is having its humanity destroyed by a parasite with every passing day.