Same reason Detroit doesn't have useful mass-transit. Entrenched interests make more money by prolonging the problem. Arguably the solution would be economical

Same reason Detroit doesn't have useful mass-transit. Entrenched interests make more money by prolonging the problem. Arguably the solution would be economically superior (vastly so!), but the folks who'd profit from it aren't in power _now_, and government lacks both the technical competency to understand what to do, and the balls to do it.