Range keeps going up. Now you can fly a big airliner between pretty much any two large airports on the planet, if you can sell the tickets for that route. The trip takes a max of, what, 20 hours or so? Cutting that down to, say, 6 hours just doesn't win you that much. Sure, there are some people who would really benefit, but I'd wager that the vast majority of travelers either get almost as much benefit from the 20-hour trip as they would from the 6-hour trip, and the vast majority of people for whom the 20-hour trip is too long to be useful would also find the 6-hour trip to be too long to be useful.
The world is only so big, and at some point, making the stuff go faster doesn't get you all that much. Personally, if I magically had the choice, I'd much rather fly on an airliner that traveled at current speeds but was more comfortable and didn't have security nonsense surrounding it than on a hypersonic airliner with the same ergonomics and security nonsense we have right now.