Until relatively recently mankind lived thousands of years mainly within the carrying capacity of their various bio-regions. I see no reason why we could not evolve back to a similar steady state economy, taking with us all the scientific knowledge we have developed.

21.000kWh/a per person is roughly 10m3 of wood, for which we need about 1,5ha of land to grow. Add 1 ha for food and perhaps 0,5 ha for roads, housing, ponds (water), etc. that brings you to 2ha per person, or 6-8 ha for a family of 4. Plenty of examples on how to farm that ultra low tech. The trick is also to keep the distances small whilst retaining some efficiency of population scale.

The Maya's solved that one already even without drought animals. Brilliant medium density, food producing, cities of 30.000 to 40.000 people. Regenerative as they societies lasted over 2000 years but their soils would have been depleted within 200.

Our only issue, beyond our ineffective psychology, is governance. Hence my interest in Systemic Consensus (SK). I've been actively using Sociocracy for the last 25 years, but SK scales up better for larger groups. (there are plenty of links in some of my comments section). As for worker ants, much there too is a matter of choice. I stoped working for commercial corporations in my early 30s. Sure, less pay, but I've never looked back and never worked more than 3 days a week for any employer. Plenty still needs to change, but might do so only if we take the first steps ourselves and learn by doing:) Tough at times, but also lots of fun.