If "rapid reusability" was a proxy goal for maintaining a given launch pace we wouldn't need any of this.

We could just construct 200 Space Shuttles and spend months refurbishing them after every flight, and still send one up every week.

The goal is to drive down launch costs, time is money, and a system that requires time consuming refurbishments is more expensive.

Mars transit takes far longer than one week. And their plan is in orbit refueling so getting a single starship to Mars takes more than one ship.