And I'm telling you that lithium-ion batteries are not a "single tech", that they've dramatically improved in power and energy density (both volumetric and gravimetric) over time. And if you doubt this, I repeat: go find and older lithium-ion battery and compare it to a new one.
As for li-air, yes, the maximum energy density of li-air is about 10x of the maximum of li-ion. Namely because it works by direct oxidation rather than intercalation, so you don't need the mass of the matrix into which the ions get intercalated. It is not a "magical tech". It exists. Like all technologies in all fields, however, you have to reach production specs. This means not only maintaining a combination of safety, reliability, longevity, efficiency, temperature range, power density (charge and discharge) and energy density, but also affordability in mass production. And to be able to guarantee that you can do all of these things to a high enough level for investors to take the risk.
As with all technologies, you start out with promise in one or two fields, but serious problems in many others that you have to deal with. With time you refine them, until all of refined to a state where the product is commercialized. Li-air has actually been advancing quite well. In the early days one of its biggest problems were efficiency and longevity, but they've made huge strides in both in recent years. Lithium sulfur still looks nearer term, but commercialization of Li-air appears to have gone from "possible" to "quite probable".