The states that do lag significantly (MS+WV) are comparable to Portugal/Poland/Greece on developmental metrics, but they only represent ~1% of the entire American population and are anomalies due to historical social economic factors (that said, this should not mean that we should give up on them - we should in fact double down and invest in upgrading social infrastructure in laggard states).
That said, every single American state and territory fall strictly in the "Very Highly Developed" category from a development standpoint and calling them "3rd world" is only minimizing the actual suffering that exists in less developed countries as well as orientalizing actual poverty upliftment in former "3rd world regions" like China, India, Turkey, Mexico, ASEAN, the Warsaw Bloc, the Balkans, Southern Europe, South America, South Korea, Taiwan, etc.
US State HDIs - https://en.m.wikipedia.org/wiki/List_of_U.S._states_and_terr...
European HDIs - https://en.m.wikipedia.org/wiki/List_of_sovereign_states_in_...
Different regions of the US became developed/first world at different times. The Mid-Atlantic and New England for example largely industrialized by the late 1800s and early 1900s, the Midwest by the 1930s, the Western US and Southwest by the 1950s, and the Southern States, Appalachia, and Puerto Rico by the 1980s-90s (thank you LBJ for your War against Poverty in the 60s).
A better comparison would be blue and red states within the same region in the US - for example, Blue Minnesota versus Red Wisconsin or Red Florida and Blue Virginia or Red New Hampshire and Blur Vermont.
The same issue exists within the EU as well btw - this is why Sweden can have some of the best developmental indicators in the world while Bulgaria can have developmental indicators comparable to developed regions of China and India.
Have you walked through the TL?
Comparing California and Texas can be interesting because the states are both dominated by a single party, so you see how both ideologies can go wrong. With Texas being like a developing country, I'm reminded of the winter power outage. They love free markets. It's not worth it to harden the electric grid for an event that rare that only lasts a few days. Picking on California, its K-12 education is in the bottom quartile.
There was a five hour long outage on Monday while the weather was perfectly lovely. And more than a week cumulative outage in March when the weather was merely a little wet.
Some Red States are an absolute mess. Some of their stats resemble third world countries.
Their education systems are shoddy. Their drinking water systems are dangerous to health. Taxes are shameful: low taxes for the wealthy but high sales taxes which hurt the poor the most.
Just for starters.