> 1. having alternatives to other commercial ventures, which are subject to their own financial viability

Alternatives to what? Commercial manned capsule ventures already have alternatives. Specifically, the only US manned capsule today, Dragon, has alternative capabilities being developed by SpaceX itself in the form of Starship, and Boeing has a capsule that keeps failing milestones but is being developed. If you are referring to the rocket, then the SLS is not compatible with any other rocket in use for any purpose, due to the SRBs. All commercial payloads are designed with smoother liquid-only rockets in mind - designing for an SRB launch adds considerable weight to the birds.

  > 2. having backup launch capability

Backup to what? What can the SLS launch that would go on another rocket?

  > 3. maintaining more relevant talent in the US

This is true.

  > 4. maintaining institutional knowledge of cutting edge aerospace tech

The SLS is not cutting edge. It's refactoring 1970's technologies. The Orion capsule might be considered modern, but again it's not cutting edge in any sense of the term.

  > 5. maintaining aerospace industrial capability in the US

Since the CRS program has been underway, this has not been in danger.