I own a copy of the book "Arcology: City in the Image of Man" that I bought when I visited Arcosanti back in 2005. I highly recommend it as its where the whole concept came from. In the book, Soleri really details why arcologies should exist and what real world ones would look like and how they would function. The second half is arcologies for various ecosystems, some for space.

Other than the space ones, the goal was never to be isolated or a biodome. They are proposed as a new type of city that is super dense and have a much smaller footprint than modern cities, that would then be surrounded by nature. So you could be living in this super megacity but then are a few minute walk away from a nature hike.

His project city in Arizona, Arcosanti. It probably could have been constructed in the 1970s-1980s if they had like, a few billion dollars worth of resources. At least to the point where it would have been economically productive enough to where it would have sustained future expansions for the next 40 years.

The vibe I also got was that figuring out how to make these things on Earth as working places will teach us how to eventually make them for space use.