In general, I like to argue that looking at the complexities of a situation provides deeper understanding, unless you get so tangled in the complexities that you come to no conclusion at all. The very interesting paper that @survinga cited is an example of the latter. To quote part of the Conclusion:
We have documented a sharp increase in state-level disparities in midlife mortality, a result consistent with an emerging epidemiological literature (Vierboom, Preston, and Hendi 2019; Montez et al. 2019). This divergence has contributed to a more unequal America; West Virginia’s midlife mortality rate is nearly double that in Minnesota. These widening geographic disparities in state-level mortality cannot be attributed to changing spatial patterns in education levels, income inequality, or rising deaths of despair. Instead, rising spatial inequality in midlife mortality results from some states experiencing dramatic overall declines in mortality across educational groups, while other states have experienced at best only modest progress.
Yet they do indeed ascribe the difference to the level of college-educated residents and to states with higher incomes.
Although states with high income have shown the way, states with lower income capacity are not inexorably constrained to rates of midlife mortality that rank among the worst in developed countries.
What the paper does state, multiple times, is that the gap in mortality is a fairly recent phenomena, not present as recently as 1994. The authors are particularly careful not to consider state politics or policies; I could not decide whether these were truly non-factors or whether they were excluded a priori. Federal Medicaid policy, however, is an exception: they document its links to lower levels of mortality over time. Levels of smoking, low cigarette taxes, and accessibility of opioids are also mentioned, but hospitals are entirely omitted.
My stance, even after reading the article, remains that I strongly disagree with you on the causes of lower lifespans in the south. Despite local exceptions, the correlation of lifespan to location is grossly explainable by political decision-making, mostly at the state rather than federal or local levels. The states with higher mortality could do more: they see the gains (or lower losses) in other states and refuse to replicate them, leaving their residents farther and farther behind. It’s a national disgrace, not an inexplicable riddle.