It seems the barbs just work better. Can't argue with history or the need to catch and eat fish.
"As a general rule it appears that the most ancient hooks were made without barbs or any other refinement. The oldest hooks that have been found in Denmark and Norway indicate that only after thousands of years were they equipped with barbs, grooves, bulges or holes to facilitate attachment of the bait and line."
http://www.mustad.no/history/hook_history.html