There are some compression driver/horn combinations that will reach up to 18 khz.I prefer the limited bandwidth capabilities of a good 2-way system for its 3D imaging and ability to convey geographic location of musical instraments.
When adding a tweeter to the mix, I have found the imaging to suffer a small amount. So while adding some "air" on top is not always a plus to me.
Just my 2 cents worth!
Ron