It's not supposed to be all easy. A big part of advancement is creating technology that enables us to reach higher with less effort. Sustainability is a big issue now that a lot of people are working towards. Once we unlock more efficient techniques of capturing solar energy, energy becomes almost a non issue until we reach another barrier that's orders of magnitude away. Space travel will reduce resource limitations too.

>I'd guess we're very close to the peak of attainable technology.

Not many people, and pretty much no research scientist, would agree with that statement. I can personally think of several technologies I'm 100% certain will exist in < 40 years that will drastically alter everything about day to day life.

Large volumes of minerals that are already in space (don't need to expend energy putting them in orbit) to build settlements, ships, etc...