Three quick-fire thoughts on why run rates have increased dramatically: 1.Big bats and smaller grounds. They bats are dryer and therefore can carry more wood. The boundary ropes have been pulled in on many grounds. Ergo, even mishits are sometimes carrying for six. 2.The fielding restrictions have made outfields so much harder to patrol. At no stage in an ODI is the captain allowed to post more than four players outside the circle. In the past, they have been allowed five. This has given quality batsmen more scope to hit boundaries. 3.Most importantly, attitude. Batsmen are not beholden to averages. They are allowed to fail in the pursuit of quick runs. This has been the single-biggest shift in limited overs cricket.