Yeah, the Concorde was interesting in that its design was optimized for cruising, so that taxiing, takeoff, and reaching cruise altitude/speed took a gargantuan amount of fuel compared to other aircraft and even to its own cruising efficiency. I can see why someone could look at that and assume that they could do better with modern design principles, including the knowledge that planes need way more passenger seats to improve the per passenger efficiency. Then again, the company that took the most concrete steps towards developing a supersonic engine pivoted to creating gas turbines for AI data centers (but was just dropped by its major customer on that, so who knows what they do next).