At present it isn't a healthy state but it is hyperbolic to suggest it is a failing state. Nations go through periods of turmoil but democratic nations typically survive and adjust to the new realities. The problem for the USA is that it has a president promoting division, has handled the coronavirus pandemic in a poor fashion, and has threatened to send in the military to contain the street violence.
The USA has a growing problem with economic inequality. The recent tax cuts only exacerbate that trend because those tax cuts support the top of the economic food chain. While unemployment is at record lows that doesn't appear to be addressing the economic inequality situation, possibly because most of those jobs are minimum wage jobs. There is some reason for optimism because wages have increased but that might be a function of various states raising the minimum wage.
I don't think the USA is becoming a failing state but it would certainly help if the leadership adopting a more creative approach to reducing the street violence rather than just threatening to call in the military. The protestors have gone too far and at both the federal and state levels the authorities seem incapable to quell the unrest.