I’m not sure why you keep saying two hours for a flight on Concorde. That was never the flight duration on its main route, which was transatlantic. Wikipedia: “While subsonic commercial jets took eight hours to fly from New York to Paris, the average supersonic flight time on the transatlantic routes was just under 3.5 hours.”
So if we are going to compare, we are talking about four hours sitting in a Concorde seat vs about nine for a regular flight.
And here’s the thing: for short hop flights in Europe, say London to Berlin, I’m okay with whatever legroom. But for flights more than two hours, I really appreciate more leg room. By the time I’m flying for four hours, like Berlin to Iceland, then I’m super thankful when I get randomly upgraded to business class.
If I was offered a four hour trip on Concorde-sized seats or an eight hour trip in business class, I’d take business class EVERY TIME. Except, of course, if one time meant I could fly on Concorde. Which I’d do for the novelty and experience, but then I’d go right back to business class.