Because they're mostly made in England, so its gonna cost more. If you're not into sound and quality, then you can always buy some Chinese made for a fraction of those British, such as Wharfedale; QUAD; Monitor Audio.
Btw, if prices of B&W's and Harbeth's shock you, try prices of the Wilson Benesch lol
Btw, if prices of B&W's and Harbeth's shock you, try prices of the Wilson Benesch lol