This is on my reading list. I've read synopses of it, and I don't think it's going to change my mind a lot. I'm still long-term pro-space-exploration, but even before this book I'd come to the conclusion that this is a lot harder than naive nerds tend to think. I think it's worth doing and probably will be done eventually, but it's gonna take a while.
I've had the thought for some time now that the most viable path to settlement in space -- if humans actually decide they want to do it -- is to settle space. Not the Moon, or Mars, or Venus, or anything else, but space itself.
In space you can build big rings and spin them for 1g gravity. We don't know if 1/6 or 1/3 gravity is enough for us to reproduce and prosper, but we know 1g is. Your environment is hermetically sealed and you control what comes in and out. You could, once you get good at this, actually create hyper-habitable environments tuned to be ideal for human life. People aren't tracking in nasty asbestos-like regolith or perchlorates or anything else you don't want.
Most reasonable near-mid term proposals for living on Mars or the Moon I've read about call for spending most time underground. Going there to do that seems pointless. Living in space itself could be much nicer.
The interior of such a ring would look nothing like this very Hollywood "luxury hotel" thing, but this little short film gives you a sense of what the relationship to the external space environment might be like:
https://www.youtube.com/watch?v=iiPmgW21rwY
Radiation is still an issue, but there's ideas for that that could work for a ring in hard space vacuum that don't work as well on a planet. One is to put a big superconductor around the ring and give it a magnetosphere. The whole habitat is a big electromagnet. Most cosmic rays and solar particles are charged. The power requirements are not as great as you'd think.
For resources asteroids are probably better than planets. The solar system is full of asteroids that appear, from what we've seen, to be incredibly rich in raw materials, and these bodies have such low gravity that you could literally pull up next to them and go dig stuff out of them. The delta-V requirements of sending stuff back to your space-city are literally at the scale of "throw it real hard." Their low mass also means you don't have to dig deep and the heavy elements didn't sink to the core. You're going to find gigantic amounts of stuff like gold, platinum, pure iridium, fissile materials, etc.
Free living space habitats could move around. There could be moving towns and cities, more or less, that could tour the solar system and pick up resources and rendezvous with each other. Think steampunk style traction cities in space, kind of.
Politically you leave behind at least some of terrestrial politics. I'm not naive enough to think people would never find anything to fight about. We're good at coming up with stuff to fight about. But the notion of battling over land pretty much goes away. Space is called space for a reason. Culture wars become less relevant if everyone's town is mobile and if you don't like your neighbors you just move your whole "pod" around. Resources seem very abundant. I don't see a ton of resource competition unless we discover some critical or massively valuable resources that genuinely are rare and available in only a few places.
In the very long term, this path leads to the evolution of an actual spacefaring civilization rather than simply a repeat of terrestrial politics on another planet. Generation ships to the stars would be a natural evolution of this. After doing this for a few hundred or a few thousand years, we'd get so good at it that the idea of a caravan of these mobile cities departing for Centauri or Tau Ceti becomes imaginable and not a total suicide mission.
Compared to this I think going to Mars is a dead end. Even if we go there and survive and prosper, now we're just doing planetary civilization again. We're back to squabbling over dirt. The real evolutionary leap is doing something different. Fish didn't come on land to stay fish.
But there's also an argument that there's no point in trying until we at least have a couple of key technologies: fusion, very good automated manufacturing, and very good robotics. Fusion is key for enabling scalable power and mobility. Automated manufacturing and very good robotics are probably key to self-sufficiency.
Trying to do the "real space age" before the key technologies exist might be akin to, say, trying to start the EV revolution with lead-acid batteries or the PC revolution with vacuum tubes. While it's technically possible to try, it's just not going to "take."