Sold out manufacturing years ago. Long term building real physical products is going to be the only value. LLMs are going to drop the price of informational value.

Late stage capitalism, protracted and targeted destruction of public education and health systems, lack of STEM focus eroding most of their massive lead in innovation, overemphasis on preservation and subsidisation of dying energy vs new energy (also contributing to innovation losses), overemphasis on meaningless politics and culture wars that ultimately mean absolutely nothing, excessive inequality resulting in the destruction of productivity in the lower ~50% of the wealth pyramid, over-extraction of the middle class leading to declining birth rates (increasing reliance on immigration), poorer health outcomes than other developed countries due to numerous factors (broken overly exploitive health insurance system, terrible diet/obesity, decreasing vaccination rates), toothless antitrust leading to monopolies/duopolies in most critical areas further exacerbating the rent-seeking and over-extraction, loss of soft power due to destruction of the state system under first Trump admin and continued decline due to tariffs and being an unreliable international partner.

So there isn't one reason, there is a ton of reasons.

It's not irrecoverable but it's bad. I honestly hope there is some wake-up moment for Americans when they realise that their leaders have been selling them out for decades now.