Yes, that's true. There would have been some other viable routes if supersonic overland flight had been possible, but it wasn't and alas still isn't - though we seem to be getting there.

I'm not sure if this has ever been positively confirmed or refuted, but I believe that CDG-JFK was always economically marginal at best, and a real dog at worst. The route was more expensive to fly (almost 200 miles, or over 5%, longer by great circle), but fuel needs meant that the aircraft was sometimes payload restricted. Most of all, the route was never as high yielding as LHR-JFK, because Paris is not a business centre in quite the same way as London. The statistic that floored me, when I worked it out, was that when BA was still operating a double-daily Concorde to JFK, it was flying 200 Concorde seats each way every day, but only about 100 subsonic first class seats. Even at Concorde's relatively low breakeven load factor, you're still needing a very high yield market to make that work.

Back to the main point of the thread, my contributions have only been to point out where the A380 fits in to the picture. I agree that the 7E7, if technically successful, has a good chance of being a commercial success as well as a replacement aircraft for the aging fleets of its size. That's why the A350 has been launched in such a hurry. But the A350 will have one big advantage over the 7E7, namely CCQ. I think that beancounters at the more financially sophisticated airlines would want to see a financial incentive from the 7E7 to overcome this handicap.

Nevertheless, there are still airports and routes where the A380 clearly has a use. The need can't be entirely bypassed by the smaller aircraft. The size of that market, however, and the speed at which it grows, will determine whether the A380 becomes a commercial success or a financial turkey.