I think that's a legitimate question. I can float a possible explanation, though I can't come up with more than a lot of circumstantial evidence (anyone following this line of politics will be aware of all that).
You mention Russia, and I think it's Russia, but you're wrong that it becomes their problem. It's their opportunity and their revenge for the Cold War and the collapse of the USSR.
Trump's run by them, in some fashion, and doesn't really know anything about the systems he's dismantling. He's just being instructed where to do the most damage, and to run his mouth in any sort of way to provide justification. It doesn't matter if he's believed.
All the stuff he's breaking is fundamental to American power, notably soft power exerted on the world, but also the R&D, the health system, the whole nine yards. Russia wishes all of that to be destroyed and not brought back. They would like it if the dollar is not the world's reserve currency. They'd like it if the world behaved as though Russian claims of the CIA lurking behind every tree overthrowing every government, were accurate and legitimate descriptions of what the USA really is.
So that's Trump and the relatively few people firmly in his corner, 'Freedom Caucus' types who've been known to openly threaten their peers with Russian blackmail, and of course Russia itself which publically made an announcement about how they expected great payback from the help they'd given Trump in this election.
Now, to Elon Musk, Peter Thiel and their ilk. Unlike Trump, they are not completely dependent on Russia. In fact some of them like Musk actively collaborate with Russia as equals. There's a catch: Russia doesn't want to deal with equals and won't help people who are too powerful. So, Elon Musk is in some ways going rogue even in this context. He is probably trying to execute Russia's goal of ruining the US because he's imagining some kind of reinvention of society, and he probably believes he'll have Russia's help behind him as he transforms society into some godawful mess he'd like, perhaps like one from his childhood.
He's likely to be horribly surprised to discover that he has not gained Russian trust, even though he's served them well. Trump is completely theirs, but Elon can't be trusted unless he's completely ruined, so what Elon wants is Bond-villain power, and no matter what happens he's not getting that fantasy fulfilled. This is his high point, while he is still doing the damage his allies need. Once that's done, he's on borrowed time.
That's what they want. None of them expect it to be 'a functioning government' for various reasons.