Earlier quoted context omitted.
For many connections that are less than 500km or so apart, a train is faster than a plane. A good rail network also connects smaller towns that don't have an airport. It can also be used to transport goods. All these uses would have to be replaced by cars and trucks if you'd only focus on planes, that's not very good for the environment.
Also, a 4 hour travel door-to-door on a plane means: * Half an hour to go to the airport * Half an hour passing security and waiting for boarding * 20 minutes between boarding and stable flight when you can start working on your laptop * One hour and 40 minutes when you can work cramped in a noisy environment with terrible air quality * 15 minutes descent and landing * 15 minutes deboarding and getting out of the air…
Only 30 minutes sounds optimistic. You also didn't count the time to recover luggage. I've seen people bringing huge suitcases on high speed trains. They couldn't take them in cabin on a flight. Planes are good past the 2 hours flight time IMHO, or across countries where there are no interconnected high speed networks (I'm writing this with Europe in mind.)