It was impractical due to physics, not some weird racism. You simply can't push a supersonic shockwave over inhabited areas, and the only way to not do that is to fly subsonic over land. Even if the oversea leg is supersonic, the tickets were much more expensive for not very much shorter flights. It wasn't a valuable proposition for most people.
2) The technology has changed. We're much better at dealing with sonic booms now. You can't get rid of them entirely, but you can reshape them. You can't send everything "up" but the longer of a tail you can make the more the sound dissipates by the time it hits the ground. There's lots of research around this and as you can imagine, incredibly important for the military. You can't fly fast spy aircraft if they are just announcing their position while flying around. Sure, there are satellites, but those are predictable by the enemy, you'll always need aircraft to do this.
Far louder though — it would wake all the pheasants up just as they’d gone to roost.
Also, Concorde's maximum range was 4,488 mi, which was calibrated to allow trans-Atlantic but not much more. Trans-Pac was not an option and even Australia to North Asia would be a stretch.
There is money in NYC-LHR (it brings BA alone $1B in revenue annually) but the market for supersonic basically vanished. In the 70s when Concorde started flying, it was certainly a step up. However, the market niche basically disappeared when the lie flat seat was developed; for a lot cheaper, you could have a sleep for six hours in a really cushy lie flat, or you could spend a crapton more to be in a much louder, more cramped cabin for only about three hours less. If you were halving a 12-16 hour journey instead, there would still be a market left, but Concorde just didn't have the ability to do so.
> having a private cabin with a shower
So any hacker considering a SST flight should also be able to afford the first class cabin.
Getting to NYC before the clock time you left London was a cool trick. It allows you to make a morning meeting in NYC without coming in the night before.
But flying subsonic leaving NYC after dinner and arriving in London for breakfast works fine. Getting to London faster in 3.5 hours travel time but 8.5 hours later clock time means losing a day in the air effectively.
The only reason Concorde did as well as it did, economically speaking, is the respective governments footed the bill for development.
Is there really that much premium traffic between Dubai and the Bay Area?
Despite two superpowers making the attempt, and plenty of time for more tries since then, Concorde is the only one that came even remotely close to something commercially viable.
I’m sure there’s a market for California to China in five hours. But is it enough to support a whole new type of aircraft? Fuel burn is going to be enormous. Maintenance on something so cutting edge will be extremely expensive. Tickets would probably cost more than a private room on a widebody.
There are no economies of scale to be had here. If there are only a handful of plausible economically-profitable routes, all of the expenditures on R&D, testing, certification, and production facilities can only be amortized across a handful of aircraft.
Once you’ve built a dozen or two of them and a handful of extra engines and spare parts… what then? There’s no point in keeping the production lines open.
From an airline’s perspective, they have to now have an entire separate chain of employees (pilots, mechanics) dedicated to another airframe that barely makes up a fraction of their fleet. That’s a lot of overhead for two or three routes.
Those are some pretty big structural disadvantages that need to be overcome in order to make a boutique supersonic route appealing.
The people who have that kind of money are going to be more interested in flying in a jet share doing mach .96 leaving when they want to leave, going where they want to go, when they want to go, how they want to go, with who they want to go with.
You get treated like a criminal for forgetting your shampoo bottle is 2 ounces too big for some dipshit TSA agent's liking, and meanwhile the ultrawealthy are shuttling around physical assets worth millions of dollars in their private jets and customs barely does more than stamp their passport.
Enforcement is super uneven, and etc, but IME, they just open your bag, find the thing, and then offer you the choice of tossing it or going back to check your bag. Depending on how much you paid for your shampoo and how much a checked bag would cost you and if you have time to do all that and then wait in line again, I expect most people toss it.