The SpaceX leadership has goals that can be opaque and need not align with NASA's. Recently, in the context of X and Tesla, they've bordered on deranged and even anti-American.
If Boeing can get out of the learning phase, even as an imperfect company, it can provide a most valuable service even if its platform is nominally second best.
1. Orion -- heavier than Dragon so you need a bigger rocket, but it should be able to dock with the space station, and it's already flown uncrewed
2. DreamChaser -- Currently being developed uncrewed, but it was originally supposed to fly with crew, and Sierra says they still want to do a crewed version. It's been moved to Cape Canaveral and is supposed to fly next year.
3. Blue Origin is rumored to be back working on some sort of orbital capsule.
Capitalism doesn't work if you don't let companies that aren't delivering fail. IMO what's probably happened at Boeing's space division is that they're not able to recruit and retain top people anymore given the explosion of new space companies.
This argument only works in competitive markets. This market is more or less a natural monopoly due to the massive upfront R&D investment and learning-by-doing requirements. NASA has to constantly wrestle with this 'force' in order to keep it an oligopoly.
If it fails to do so, it should stop the experiment and go back to in-housing everything. Only with an oligopoly (or better) does the American public benefit at all from privatization.
As for NASA "in-housing" everything, that's always been a continuum. Mercury is probably the last spacecraft that you could really say NASA designed internally that flew. Even operationally, for the last part of the Shuttle program, most all of the operations were done by the United Space Alliance.
That said, I agree that NASA has a role to play to encourage diversity and competition, and IMO they've done that with Orion, Dragon, and DreamChaser. Just because SpaceX could use some competition doesn't mean it has to be Boeing.
Maybe instead of pumping money into the husk of Boeing they could try to give some to DreamChaser?
Hope they'll continue.
Also I'm not sure if Boeing's goals are more aligned with NASA's than SpaceX's ones with those of general public - and that public would probably disapprove such things as SLS.
Musk may be huffing the right wing nonsense too much, but I don't know if he has actually done anything anti-american(though supporting someone as obviously corrupt as Trump could be considered so I suppose), much of the headlines about him appear to be clickbait nonsense.
SpaceX can't do jack shit without Gov approval, so it wouldn't really matter if they had ulterior motives.