Until Artemis actually flies a comparable number of missions, any advantage in reliability is pure speculation. Which is not a good way to approach crewed spaceflight. I don't think the two programs are as different as you think, prospectively: both take great care to ensure that their vehicles don't fail. Starships may be cheaper than the SLS, but they're still very expensive. SpaceX doesn't go into a flight expecting to lose a vehicle. The difference in culture is more in the reaction to failure. As a private company, SpaceX moves very quickly in the wake of failure, whereas NASA has in recent decades become much more cautious once a failure has occurred. And while you say SpaceX is more tolerant of risk, I would note that they've never flown a crew on a launch vehicle that had only one previous unmanned launch. Falcon 9 had 85 unmanned launches before there was a crew aboard. And they expect to launch 100 unmanned Starships before they fly one with a crew.

Now which program seems the more risk tolerant?