The most important work of "How to Build the Future" is political work - reforming our property relations, for example, so that we aren't organizing our economic lives around feudal holdovers like land titles. Who gives a shit if Elon Musk can connect his brain to the Internet and live forever as a sentient AI, while the rest of humanity drinks ditch water and lives small, dull lives?
Cheaper access to space would make lives easier for humans on Earth, give us better internet through the use LEO satellites. We would be able to mine space rocks and bring it back to Earth, reducing some material scarcity on Earth. Same for space manufacturing.
I'm circumspect about studying decision theory from an AI perspective will be very helpful in learning how to modulate our own decision processes. Most of it is focused on finding ways to keep AIs from doing weird things that humans already don't do anyway.