Why might Starship be considered a logical evolution potentially replacing current NASA systems like the SLS?

Due to its lower projected cost per launch for achieving heavy-lift, reusable infrastructure.

The necessity for SpaceX's continued role is tied to the goal of sustained exploration to the Moon or Mars. Analysts suggest that Starship represents the logical evolution for these future missions primarily because of its design intent to be fully and rapidly reusable, which is projected to result in a significantly lower cost per launch compared to existing systems like NASA's Space Launch System (SLS). If NASA aims for sustained presence off-world, partnering with the entity actively building this highly capable, lower-cost, reusable heavy-lift infrastructure becomes the pragmatic necessity rather than attempting to construct a slower, competing system.