I just listened to a clip of Joe Rogan being excited by the hypothetical prospect of not needing to sleep and having an additional eight hours available each day. What would people actually do if they had more time?

Like Rogan and his guest, many people would probably imagine eight incredible hours doing all kinds of fun stuff. Unfortunately, I think the true answer is way less exciting, as we probably would just spend most of the extra time working more. What makes me confident is that we have already been through such an experiment many times throughout history. Due to technological development, many people today are utilizing their labor to produce many times the amounts of products we used to a few decades ago. To maintain the lifestyle of someone working full-time in the 1950s with the technology available then, you obviously had to work full-time. However, to sustainably maintain the same standard of living in a western country today, people would only need to work a small fraction of a full-time schedule. 

Whenever our labor becomes more efficient in producing products, or we get a better paying job, and our income increases, we all have the option of at least asking to work fewer hours and pass on the wage increase. Very few people seem to be willing to sacrifice income increases for additional leisure time. In many western countries, we seem to have reached some kind of equilibrium at around 35-45 hours of labor per week. For the same reason why we will not start to see a broad decline in hours worked and reduce income growth accordingly anytime soon, the additional resources of adding more available hours would be primarily spent by working more to increase income further. As long as people maximize wealth relative to, or their perception of others, the hamster-wheel of prioritizing income before leisure will likely continue to beat technological growth in the future as well.