it would have been self-sustainable. If there was any water there.
However much i like the visuals of solieris vision, concrete, hippie and brutalist architecture in general, i find the idea of life a city that cannot grow but inwards pretty grim.
Not enough, I'd guess, but you could afford basic water and food if you can sell something else at a high enough price.
[0]: https://cosanti.com/
Getting to self sustainability always suffers from bootstrap problems, and closed loop living systems of this sort, even at 5,000 people, would suffer from lack of domain expertise or specialized resources to be truly self sustainable. At least unless they either target a low technological level of life or pick the exact 5,000 people needed to keep things going.
That's not meant to be a criticism of this project. If anything the project has strong value in helping to understand roadblocks to small self-sustaining communities, while also contributing to the zeitgeist of fascinating, quirky niche communities that enhance our culture in valuable ways.