The individual Falcon turn-around is slow (months of refurb), and the record half-month ones swapped some engines. B1067's 30-reuse is a ship of Theseus rebuilt over 4+ years.
Feh, swapping engine is not an option for the first few initial Mars trips, unless its payload also contains engines (can't imagine the scissor-lift payload either that needs to go with).
The head of SDI formed the Mars Society with Zubrin. He was originally going to run SpaceX as Chief Engineer (cite: Liftoff) but he instead got appointed NASA admin and directed the first few $billion to a zero-experience SpaceX. This same SDI head then formed something called SDA in 2017 under Trump which is the platform for Golden Dome, or "the SDI 2.0".
This is a multi-trillion dollar program which only Musk has been awarded contracts (as of Nov 2025) and involves the total weaponization of space.