I dont know i agree. Trans-antlantic flights kind of suck. If i was doing tourist things (and the cost point was right) i would definitely prefer a 3 hour flight. Not sure i would pay double for it, but i do think there is a market for this.
But i suspect even if its double, that would still be enough to attract business class peeps, which might make it economically viable.
I kinda doubt that dynamic changes.