Horns have unexploited potential. Lets get busy harvesting their potential. Most other options seem to have reached their limits long ago
Horns are great. They are the BEST solution for many applications.
However, you cannot dismiss other options so summarily. You are generalizing too much.
A good horn in the right setup can be the optimal solution, just as a conventional dynamic driver can be optimal in another situation.
For example: What about the midrange. Most horn designs crossover around 800 to 1000 Hz. Many people believe this is not a good region to have a crossover, as it is right bang square center in the sweetspot of all music.
All designs involve trade offs. Horns have some extremely useful characteristics for live audio and stadium audio. In fact they are probably the best #1 choice in most large venue live applications - as the narrow dispersion allows better control of the sound field so each listener gets an optimal experience. Line arrays are another powerful tool for live venues. However, these advantages do not always translate to making these designs the #1 choice in the home or in a studio.
Horses for courses.