people are far more selfish these days.
classic wow will be a pain just to find groups, in classic (given wow's predecessors) it was commonplace to allow 3-4 hours when looking for a dungeon group and also completing the dungeon. given the state of the game now, i would hesitate people allow more than 30 minutes (less so, perhaps 20 minutes if tank/healer) to complete a dungeon. what you will see if a complete failure of people to dedicate themselves to a group.