Many of the people I mentioned already travel in luxurious conditions, and the economics for luxury aviation are well-explored. It misses the fundamental issue here though. Time spent traveling is time that isn't spent setting up for an event or meeting with fans/media/business interests. You can't solve that with classical music.
It's two different problems. Yes, if you absolutely positively have to be in London in four hours to Sign The Big Contract, you'll pay whatever the Concorde replacement charges and put up with whatever experience it offers.
But there's a huge market in conventional tourists that have more flexibility and could choose from more options.
A typical tourist-class trip is going to be one day of "Travel Misery Time" followed by "Actual Vacation" followed by another full day of "Travel Misery Time".
Yeah, theoretically it might be less than a full day door-to-door, but if you're not an experienced traveler with expert experience in managing timing, baggage rules, TSA procedures du jour, and navigating the facilities, you're probably writing off the whole day of arrival and departure. Nibbling away a couple hours in the metal death cylinder doesn't solve that.
What if we said "we can swap one day of Travel Misery Time for two days of Resort on Wheels Time?" You might get fewer days at the destination, but an overall more enjoyable trip. Rail can offer that. Even today's Amtrak long-hauls offer a comfortable sleeper room, real food, and actual scenery, and no airport suffering, and there's no reason future offerings couldn't introduce other amenities (i. e. a spa car, or scheduled entertainment).
At human levels of expense, I think it's not. I traveled Amtrak sleeper on a 24-hour ride. There was no shower, so I couldn't have gone 48 hours, but otherwise it was end-to-end way more pleasant than any international flight I've ever taken.
