While I think there is an "S" curve, I see we have quite a lot more to learn, much longer than a few hundred years' worth. I'd say more on the order of hundreds

While I think there is an "S" curve, I see we have quite a lot more to learn, much longer than a few hundred years' worth. I'd say more on the order of hundreds of millennia more at a minimum, because the scales I see possible are so vast. My metric is where we are on the Kardashev scale, how resilient we are to extinction-level events, and our time horizon. The ultimate "we're pretty close to knowing all the practical stuff" level being figuring out how to work around the entropic end of the universe. I count indefinite life extension among the practical tech tree, and once we accomplish that, the range of "practical" also expands. Even before all that, we're nowhere close to various practical limits we've calculated as theoretically possible in energy extraction, energy conversion, energy conservation, matter properties (compression strength, tension strength, torsion strength, and so on), computational density, information density, etc. For most of our species' history in geological time, we've barely edged over from sentience to sapience. On that scale, we're still at the boundary layer edge, and have yet to really delve into and establish ourselves within the time stream into sapience.