Huh??? You make no sense at all. Britain didn't cut them off into their own ghettos. They did that themselves since they are incapable of joining the modern world, and definitely don't want to become part of the western world. Britain's only mistake was letting them in the country, the same mistake we are making.
I wasn't saying that Britain consciously put them into ghettos. They just ignored them, like most of the rest of Europe has, and that's how it ended up.
As for the rest of your post, I think you sweep a pretty broad brush with your word "they". I think plenty of Muslims are capable of joining the modern world. Living with the rest of America, instead of living apart, may help more join in.