Wouldn't it be reasonable to insist that the "host" nations go to great lengths, to capture them? We haven't heard very much, about such efforts, in muslim and arab locations.
Why? Are the efforts taking place, or not? Are they taking place, without success?
You may have not "heard very much," but much has been reported (and doubtless much more has not been). Pakistan is a major haven, but the Pakis are working hard on this, are cooperating with U.S. intelligence, and their police and military personel are putting their lives in danger on an almost daily basis. Pakistan has rounded up over 400 al-Qaeda, including some of the biggest fish yet netted.