I have some time on my hands, so let's stir the soup[1].

Based on this premise from a previous post:
That's why it will be up to private enterprise to open the space frontier if it ever is. They key to that, is making a buck, as in the saying "No bucks, no Buck Rodgers". If it can't economically sustain itself it won't matter much how or when we got there. We won't be able to stay. I suggest there are plenty of abandoned mining towns in the US West that proves that out.

Now private enterprise doesn't a-priori *need* the government to assist
other than if they have existing contracts that enable their space
technology, as long as it's on a non-exclusionary basis, all is well. As
it turns out I think you can make a compelling argument that without
COTS now evolved into Commercial Crew, SpaceX would not exist. Maybe
companies like Virgin Galactic and Blue Origin and even Electron Rocket
would but they obviously aren't as far along as SpaceX has gotten with
government help.

Now given that, HERE is my argument for why SpaceX (or possibly Blue
Origin) should mount a flags and footprint mission to the Mars ASAP.
Every dollar wasted on SLS, albeit a drop in the bucket as far as the
federal budget is concerned, were that money diverted to developing or
subcontracting private enterprise to develop actual USEFUL technology
for Mars habitation, such as growing food, nuclear power, habitat
creation, sustainable life support, studies of human physiology in low
gravity, etc. etc. All of that would be a HUGE BOON to human space
exploration and expansion. As opposed to wasting billions on a rocket
and launch system that has actually NOTHING to do with Mars and can
barely get us back to the moon, at a tremendous expense and in a way
known to be unsustainable, i.e. unable to self-sustain.

A mission to Mars with a short stay duration and return would kill SLS.
Once a fait accompli, there is no point to it. Then and perhaps only
then will the money be reassigned into more productive means. Of course
there is always a risk it would NOT be assigned to space. That is a
risk. Companies like SpaceX obviously must plan to go it alone in any
case. However, if it enables the former it is well worth the risk.

A flags and footprints mission to the Moon by private enterprise *might*
accomplish the same goal. That could certainly be mounted even sooner
and at far less expense and I'd be willing to try it followed by a wait
and see to see if that would be enough to kill off SLS. I fear not.

The REAL billion dollar question is how to re-organize the government
space program to outlast the administrations that administer it. Maybe
the only way to do that is via an international consortium. I can't see
that being very successful either unless it was non-governmental. On the
other hand, if it's an NGO I'm convinced there won't be enough money
involved to make a difference.

Dave

[1] or substitute your preferred substance...