I hope Bridenstine is not correct and that he somehow knows that Musk’s Starship will not prove an adequate lander.
I hope Musk and his people, by far the most qualified and experienced people in the development of rockets and spacecraft anywhere on Earth, can and will perfect the lander. If Space X is not successful then there will be no US manned Moon landing in the next decade. In that case the entire purpose of Artemis is suspect.