A fan will also work for insect control and to speed up the drying process, especially in the beginning when there's a lot of moisture and fruit flies will be attracted to your foods.
I suspect in paleo times, if they dried fruits at all, they would have no way to stop the fruit flies from proliferating, and so they would inevitably lose some of the fruits to them during the drying process. Unless they took turns with a hand fan. They may have even welcomed the fruit flies, as the larva likely turns some of the sugar from the fruits into protein. Even to this day there are some people who intentionally grow fly maggots from meat or cheese to increase nutrient availability, even though they clearly lose some food energy in the process.
Wine and vinegar making are also likely to have been done in paleo times.
All of that said, it's unlikely that most paleo people in most of the world would've had access to massive quantities of fruits, and even if they did, their wild fruits would likely not have been as sweet as ours. They may however have used honey to increase sweetness in order to make wine and vinegar.