Exactly. We would be better off disrupting the BS of air travel then building out train networks. I've often dreamed of a world that comes to its senses and realizes that adding all the extra bull to flying hasn't done any good and there was a consistent effort to eliminate it all.

Imagine if flying was as easy as getting on a train or bus. Buy a pass. Sign up for a slot on a flight online. Show up DIRECTLY to the gate (your are pre-cleared by TSA and AI verified your face on exit of the vehicle). Someone else or some automated car mover parks your car, drop your bag off IMMEDIATELY on a conveyor belt and forget about it (let some AI system handle its tracking and tagging), then just board with a valid pass. No lines, no checkin process, no bag tagging, per-screened, no fuss. In your seat within 5 minutes of exiting your car. Similar experience on the backend. You exit, grab your bag quickly (not sure how this would work, mass bag pile or some tech to quickly exfiltrate your bag from the plane), then get on a shuttle to a rental car center or bus/taxi/uber center to wherever you are going. Or some automated car mover retrieves your car from a parking garage and has it ready for you outside. Maybe even has your bags carried by drone to it quickly.

That does nothing about the fact that flying is destroying our environment and emits greenhouse gas emissions 2 orders of magnitude over the same trip by train.

If you ammortize the environmental impact of building the rail network over all the rail trips, it might swing the other way. Especially if someone figures out carbon neutral air travel in the next decade.

If we are factoring in imaginary future tech then someone could invent carbon neutral trains

That's theoretically true, but more far-fetched considering the amount of steel involved.

Synthesizing jet fuel from atmospheric carbon, directly or indirectly, is an active area of research and will likely happen at some point.