If this aircraft flies at Mach speed above a deserted desert, does it make a boom?
It's "about as loud as a car door closing"? How close am I to this car door? If the answer is "that's you, closing it", then it's still pretty loud.
"The long, slender design of the aircraft is the key to achieving a low sonic boom."
Think about how noise-cancelling headphones work! So, maybe the best solution is adding specifically designed wing/body structures (& speakers?), so that a supersonic airplane generates its own specific anti-noise/anti-shockwave (instead of trying to change the shape/design of the airplane in any extreme way)!
As long as it's a soft "whump" and not a soft "bang" it would be ok. The problem isn't just the noise, it's the suddenness (unlike a normal jet roar which builds and you hardly notice).
Beautiful plane, but far from the Match 2 of the Concorde.
" . . . environmental regulations . . . . were often deliberately prejudiced against supersonic flight."
UK & France had it and USA did not so it was necessary to stop it.
Give it a couple weeks and China will start building their own, it'll just look a whole lot like the one Lockheed is building!
Fuel? Do these engineers live in a bubble too? Don't they know about Global Warming? No more jetliners, or if we really must have them, then do it on some other planet. Airline 'traffic' has to be reduced by 50 % or more, which will probably make it something extremely exclusive or none existent. Climate Change folks, we'll be walking soon.

Everything old is new again:
Why? and for whom? Obviously, not us mere mortals. Whose authorizing all this waste of our tax money for these elite government blood suckers?