bit late but...
My MTB did around 1,500 miles before the tyres for worn through (half of that touring with tent etc, the other half commuting/pleasure).
My OH's MTB didn't get 1,000 miles out of it before touring killed it (somehow getting 3 very deep slashes in the side wall, but we were having daily punctures from it before that)
My touring bike did 9,000 miles before we replaced the rear tyre (Schwalbe Marathon Extremes) because it was the last opportunity to get decent ones before heading off into the middle east and beyond... the front is still on the bike at 9,250 miles (dog attack terminated the tour)... the rear tyre probably only had another couple of thousand miles left in it before it was replaced.
On his touring bike (Schwalbe Marathon Extremes), well the first rear one died at 4,500 miles with a blow out (side wall failed).
the front was replaced at around 6,500 miles and kept as a spare... still has probably 2,000 miles in it.
Now we wait to see what the road bikes get from their factory tyres before changing them...