Boeing has competition in the USA?
Nationalizing Boeing will only make the problem worse, because guess what: Nationalized companies won't fail, so there is absolutely no incentive to be good which is worse than the situation now.
No doubt the US government will bail out Boeing at least once, but I would expect that to be it. A one last chance point of no return. If Boeing ever gets to that point and still fails further, the US will have no choice but to have them fail.
On the plus side, it's not like Boeing going under is an actual national security threat. There is nothing wrong with relying on Airbus who will no doubt move into the newly vacant market spaces, we are all NATO allies aren't we? To say nothing of Lockheed Martin and Northrop Grumman who do a better job of military aviation anyway.
https://www.corporatejetinvestor.com/news/us-government-impo...
https://en.wikipedia.org/wiki/CSeries_dumping_petition_by_Bo...
I'm also not sure "we'll probably only bail you out once" is a great position to take in motivating Boeing and its ownership and governance to make major changes to survive as a company.
Then you haven't been paying attention. Most of their problems have been in the military aviation sector, between problems and failures in the KC-46 Pegasus, V-2 Osprey, Air Force One version 2, F-15EX, and F/A-18 Super Hornet programmes among others.
Their failures in civilian aviation and space are all intrinsically linked with their military failures all likely having common causes, it's plaguing their entire company from top to bottom across all their markets.