I only roll blunts if im smoking with a friend or two. Thanks to the burning properties of the tobacco leaf it wont burn down significantly when you arn't hitting it. Then consider that with a blunt you're smoking the entire thing, whereas with bowls some smoke and thc will accumulate on the inner surface of the piece. Another thing people don't realize is that once they feel stoned enough they can put the blunt out and re-light it when they desire.

Blunts are definately wasteful if they arn't rolled properly, if they only burn for five minutes you did something wrong.