I disagree that it was “this country” in terms of the choice of individuals that “chose” air travel. If it were, then all of our airports, regional and international, would have been privately owned and operated and never received a dime of tax money in revenue. But instead it was central planning and government funding that brought it about—same with highways—while private railroads (in both infrastructure and rolling stock), which helped the country win WWI and WWII, were regulated and taxed nearly into oblivion, certainly 100 percent in terms of their passenger business and for the most part with their freight business.
BTW, I think you overestimated California HSR, whose last total costs were figured to be $100 billion (or $125 million per mile based on the 800-mile estimate, which by itself is about five times more expensive than what they spend on high speed rail elsewhere on the planet save in England). $500 billion works out to the unheard-of per-unit-length cost of $625 million per mile, and so far, the most expensive high-speed rail proposal is Amtrak’s one for the duplicate Northeast Corridor or “next-generation” service currently estimated at $151 billion, or (based on 438 route miles between Washington and Boston) a whopping $345 million per mile on average. These kind of cost estimates seem to only happen in this country; in France, they spend about $12 million to $20 million per mile.
Going back to the 1960s, the federal government was promising that the Pennsylvania Railroad’s Metroliner (later Penn Central) would eventually travel at 160 mph, BTW (and “eventually” did not mean waiting until the third decade of the twenty-first century).