With the roll-out of more sophisticated air traffic control systems that will allow denser traffic, higher frequency landing / take-offs, I don't see the sense in fixed systems like rail.
It obviously makes a lot more sense in places like Japan or even parts of Europe, but in the USA, where you need to traverse huge swaths of uninhabitable and even inhospitable and unpredictable land, it simply makes no sense.
Take Texas for example. All the idiots that have been moving to Texas from self-absorbed and myopic cesspools of self-importance keep crying about public transportation and high speed rail to connect the San Antonio, Dallas, Houston triangle; but no one wants to address the question as to why. You could and already can travel those paths by air and it will only get faster and cheaper with the improved air traffic control system when fully rolled out.
Do we think that high speed rail will enjoy the freedom that current AMTRAK does where you just drive up, hop on the train and off you go? No! You will have to also go through the TSA security bullshit and you will still have to go to specific locations to get on. It just makes no sense.
I would much rather see some sort of automated flight between regular airports on regional hops like the Texas triangle.
Edit: ... If at all. Something somewhat related that has baffled me for years now. Is why do people, especially in the tech industry need to travel so much? Of all people, why has the tech industry not solved the remote working issue? It's like we are using steam power to make electricity. Again, it makes no sense.