>Current technologies are too far behind in speed though.
That depends entirely on the distance traveled; no one is suggesting a replacement of transcontinental flights with trains. But there's plenty of medium and short haul flights (for example) that would be far more comfortable on a train with little difference in total travel time once you've factored airport security overhead.
I'll give you a practical example: my wife and I live in Houston and regularly visit New Orleans. It's a one hour and five minute flight on Southwest which is one of the few airlines that still allow two suitcases per passenger for free. That's a five to six hour drive if I choose to go by car and with rare exception I choose to drive. I'm happy to trade two to three more hours on the road versus the hassle of dealing with the airport.
>Passengers will trade better wifi, food, space, etc, in exchange for longer travel times but only up to a point.
The time to travel between Houston to New Orleans would be two to three hours by high speed train. That's competitive with the Southwest flight and fast enough I'd seriously consider versus driving myself. In fact at those speeds I'd start looking at longer trips either to Mexico, farther West to Arizona, New Mexico or Colorado or farther East to tourist destinations there. At least for me it would increase my travel options and I'd be sure to take advantage over it over flying.