"They're superior in every respect"
In terms of present day speed and not requiring connecting infrastructure they're superior, but that's about it. On the other hand they require more infrastructure at each end, have far increased per-passenger-mile fuel costs (increasing exponentially unless you pack people in like sardines) and are more susceptible to service disruptions from factors like weather. Unlike airports, train stations can be put right in the center of cities, even underground as they have done in many places in Europe.
Logically, high speed rail just make more sense for high-demand intercity routes. Airplanes use most their energy traveling perpendicular to the desired direction of travel (i.e. getting up to 33,000 ft). As technology develops and you create increasingly ideal conditions at ground level (ultimately this means Maglev inside vacuum tunnels) the result is going to be inherently superior to transportation requiring a costly and uncomfortable vertical dogleg.