I am a pretty big SpaceX fan, but so far, they've been tackling challenges that lend themselves to a rapid iteration if given sufficient capital.
Rapidly iterating on the incredible engineering difficulties inherent in building a reusable rocket does not mean you can do the same thing with an interplanetary mission that involves at least ~5 months of travel one way.
They need a whole other class of scientists and engineers to solve the "keeping a human alive for years in spacecraft/colony" problem. It just seems like a fundamentally different class of problem to me, and that SpaceX's strength of rapid iteration may be hardly applicable to this problem.
I still thing a lot of it transfers over, especially if Starship works as intended - send Starships to Mars often with proof of concept tech and any customer payloads & have part of it pressurized with prototype life support system. If it works fine after the trips on multiple occasions, you can be reasonably sure it will work with a crew as well.
Possibly more sure than the "classic" testing (and paperwork) heavy model that usually does very few actuall test flights due to costs.
Rapidly iterating on the incredible engineering difficulties inherent in building a reusable rocket does not mean you can do the same thing with an interplanetary mission that involves at least ~5 months of travel one way.
They need a whole other class of scientists and engineers to solve the "keeping a human alive for years in spacecraft/colony" problem. It just seems like a fundamentally different class of problem to me, and that SpaceX's strength of rapid iteration may be hardly applicable to this problem.