Planes are technically faster once they get going, but the processes related to security, boarding, and the location of airports often being very far from city

Planes are technically faster once they get going, but the processes related to security, boarding, and the location of airports often being very far from city centres negates this for HSR train journeys <= 4 hours long. In theory you could replicate all the worst features of airports with rail, too, I suppose, but for obvious reasons it's easier to build a train station in a city centre than an airport.