I haven't read the trilogy, but understand the "greening of Mars" scenario.
How many cannisters of greenhouse gasses would you have to dump on Mars, to start an "atmosphere"?
The 1970s fad was O'Neil colonies, it was all worked out in fine detail, with costings, how the "island" space colonies would pay for themselves ...
Before that we had Von Braun's space stations.
Before that we had Tsiolkovski.
Before that we had .....
I think colonising the solar system is a great idea, but where's the incentive, how would it get started?
Jerry Pounelle reckoned we had maybe 100 years to "get into space", after which natural resources would start running out, and we'd be "stuck on earth" forever ......