> Most governments manage to pass a budget every year.
Not exactly. Two things are going on here that makes the US "special". I would argue they're both design mistakes in the US government, its proponents will doubtless chime in that it's supposed to be like this, and presumably they are proud of the results...
1. Appropriations bills. In most countries it is seen as a foregone conclusion that the government should continue to operate. Politicians steer, but in their absence the ship of state continues onwards on auto-pilot. The US has never entirely worked that way, and last century the GOP intentionally destroyed some of the mechanisms to let it keep running in their absence, because of course they did. So, Congress must explicitly pass bills at least once per year that say the government will pay for things, or else important government functions just stop. Nothing like these Appropriations Bills exists in most countries.
2. Separate Executive. In most democratic countries there is ultimately a single elected power, even if it looks on the surface as though there are two or more political power centres, one of them is actually running everything. In this situation there is no conflict between policy and budget, so of course a "government budget" will pass.
One of the few upsides to another US civil war is it's likely that there would be an opportunity to redesign the US government in the aftermath. We've learned a lot about how to design governments since the 18th century.