Let's unpack that:
> SLS is about maintaining the ability of the US to build rocket engines like the RS-25 and those massive SRBs
...but why? They're expensive and bad. Maybe the US SHOULD forget about them.
> The Government is worried about waking up some morning and China has leapfrogged us to the Moon and it'll take 20 years for us to institutionally remember how to get back there.
The SLS was indeed created back when this sounded reasonable. But it no longer does. The US can go to the moon now. They just have to pay SpaceX to do it, and failing that, Rocket Lab. But asking Boeing to do it is pretty guaranteed to be a bad idea.
> And SpaceX has not yet demonstrated the ability to land humans on the Moon while NASA has.
Boeing has demonstrated a willingness to not live up to its former glory though. And let's be honest here, this is not NASA vs SpaceX. This is Boeing vs SpaceX. That's the main contractor doing the vast majority of the work. Boeing, as you might remember, STILL haven't shown then can get humans to the ISS anymore! We are still waiting for Starliner to come online.
> They're making sure that we can definitely still use big dumb stupid expensive technology to get there.
I guess...
> If Starship works they may wind up pivoting away from SLS in the future
We can only hope! But again, Falcon Heavy exists NOW.