Truthfully, why should one be a citizen? It seems like you get all of the benefits of citizenship, plus the benefits of being a non-citizen, by being a non-citizen.
I'm pretty sure that Takoma Park, a close-in suburb of DC, has this already. Whether noncitizens not working for e.g. the IMF can afford to live in Takoma Park might be another question.
Truthfully, why should one be a citizen? It seems like you get all of the benefits of citizenship, plus the benefits of being a non-citizen, by being a non-citizen.
Citizenship comes with only drawbacks these days.