I think these films appeal more to the British audience, than American. Unfortunately the British Film Industries doesn't by any account match up to that of Hollywood; it's vastly overshadowed by the Asian industry, French, and Bollywood. The British public doesn't seem to have much interest in British films, because Hollywood force feeds us shitty remakes of good films. If you want a good British film to watch have a look at Dead Man's Shoes, or This Is England (both by Shane Meadows). I've not seen the new film, but what I remember of 28 Days Later I wasn't greatly impressed.