I remember seeing and doting over every one of these Back in the Day.
In addition to the fannish L-5 society, there was a movement among right-leaning SF writers to promote space colonies. I doted over those stories and novels, too.
I eventually soured on the idea. A lot of the people pushing the notion I met at conventions seemed all talk, and seemed . . . off. Cranky. And their ideas and plans hardly ever changed.
Then there was this panel discussion about the future of cities at I-Con in 1990, and Bruce Sterling fielded a question about space colonies. He trashed the idea with a knowledgeable snarkery that was awesome and terrifying. It was like a great weight was lifted from my shoulders. Like: :"Yeah, that stuff is kind of wacky, isn't it?"