I also think the whole idea of one Mars city is not what will happen.

The greatest attraction of Mars is free, open land without government & taxes, where small groups of like minded people can start again and try all sorts of social & political experiments that would be impossible on Earth because of entrenched interests & all land being owned by someone and a State.

Just think a group of 50 young couples buys a 2nd hand Starship and pre-orders so Starship deliveries of robots and materials on land at least 50km from the nearest settlement.
They can make polycarbonate greenhouses from native CO2 & H2O & sunlight & be self sufficient in everything except small, lightweight electronics.

No taxes. No laws. Just a small community making its own rules and living off the land.

This will be very attractive to many.