Elon Musk wants to build an independent city on Mars within 20 years. SpaceX President Gwynne Shotwell said the same thing, two years ago.
This effort is a long-term goal for SpaceX. Therefore, the Starship spacecraft will be important for building a city on Mars.
Moreover, Starship with its large size is claimed to be able to carry up to 150 metric tons. SpaceX also wants to use Starship for cargo and crew missions.
SpaceX itself is making good progress in reusable rocket and spacecraft technology. However, it would take 20 years to build a city on Mars.
This depends on technology, successful landings, and overcoming challenges with the government. SpaceX is confident that it can do this.