This article comes off as _very_ optimistic, to the point of making some really bad assumptions and misrepresenting data. The bit about sitting in a sonic boom

This article comes off as _very_ optimistic, to the point of making some really bad assumptions and misrepresenting data. The bit about sitting in a sonic boom simulator chamber is just silly — the author's subjective opinion about the loudness of a sonic boom has no bearing on reality, and fails to factor in that sonic booms during e.g. Bongo II (1964) shattered windows not because of the sheer volume of the sonic booms, but because this pressure wave would strike the large surface area of a window nearly all at once, putting a fair amount of energy into it in doing so. Almost as silly is the line extrapolating speed trends in commercial aviation over time; it reads like xkcd#605. It completely ignores the different regimes of high-speed flight and the limitations posed by it. 2,500mph is roughly Mach 3.2 at sea level, or nearly 3.8 at 60,000ft. At Mach 2, you need to start seriously considering thermal issues caused by friction related to parasitic drag and the paint/coating of the aircraft; at Mach 3, these become primary design constraints, and active cooling systems have to be deeply integrated into the airframe. This is to say nothing of the exotic engine design decisions that have to be made in these regimes. Much north of Mach 4, transporting any useful load becomes borderline impractical in-atmosphere with current technology. Ignoring fuel economy issues since I brought this up in a separate comment: since the introduction of the Concorde, the major focuses of aviation development have been on safety, reliability, and automation (all of which are strongly linked). "We live in the safest era of aviation in history" is an evergreen statement thanks to those advancements, and aviation incidents — while tragic and unfortunately not completely eliminated yet — claim fewer lives with each passing year (as a proportion of passenger-miles travelled).