But to me at least, the speed is the smallest issues with airplane travel.
The bigger issue is that it's just a miserable user experience all the way around: finding and buying tickets, going through security, boarding the plane, eating and being entertained on the plane, sitting in bad chairs, unpleasant bathrooms, and then you get to the general societal increase in mental illness meaning you might have to deal with some onboard drama, etc.
I'd prefer to drive anywhere that's not over an ocean these days even if the flight was at Mach 10.
Eighty years ago we didn't have laptops to work from, or global connectivity. Now, we do. I'm thinking about total time, not only the travel time part.
Thinking total time, I can leave the office a day in advance as my 6 hour flight of 3000 miles now takes 20 hours. I can spend an evening in a large properly convertible chair/bed, have a stroll around the next day, perhaps enjoy the observation deck or a sit-down meal. I can have a proper day's work while on the move, watch a movie in comfort, have another sleep adjusting to timezone, and arrive at the destination in great comfort.
Instead of chasing speed, why are we not chasing that? It could be an airship. It could be a hydrofoil at sea or in waterways. It could be a train! It's a superior form of travel.
Besides due to regulations a lot of airline design is stuck in the 60s/70s as redesign to modern standards is insanely expensive.
Flying is a nightmare due to everything that is _not_ sitting on a plane. Booking, checking-in, dealing with labyrinth airport layouts, needing to walk literally miles to your gate in some instances, your own government treating you like a career criminal ala TSA, etc.
Sitting on the plane and going to sleep for a few hours is the best part of the whole ordeal.
More pre-check security. Less hoopla. Many people have to drive 1hr+ to fly in the US.
Maybe aerospace engineering experts can weigh in on the fuel inefficiency issues, but definitely the combination of cost + limited flight paths made supersonic commercial flights nonviable from a business perspective
There are companies that are researching the possibilities but there are many hurtles such as cost, noise, and pollution.
