Being a developed nation is a moving target. Both the requirements change as new technologies are discovered and the scale of infrastructure goes up as your country grows.
The US stopped seriously investing in itself over 40 years ago. We've been coasting on prior infrastructure making tiny improvements here and there. What we haven't been doing is keeping up with the other developed, or even many developing, nations of the world.
New transit infrastructure, updating the grid, building new schools, updating our systems of government, overhauling healthcare, and generally adding modern approaches to community support have never truly happened. The coasting on old wins is finally dragging to a halt. The US is rapidly losing on the education front, the healthcare front, civil rights, transit, community support, overall skills, and even military resources. We pay a lot in some areas and essentially none in others, but across the board it's not working to make us competitive on the world stage. Instead, our wealth is going to a handful of billionaires.
Every dollar shifted to a top 1%-er's bank account i many dollars lost in money that should be spent many times making out communities better. It should be routed through a company to build a school, whose salaries get spent, which then gets used to do more things, again and again. That dollar should move around to help us build the infrastructure back into a developed nation. As it stands, it instead is denied to us, and our children are faced with an empire collapsing to a lost class war where greed overcame a nation.
TACO style fascism rules the day.