The flipside of it is that players are also taught on how to fall on their stomach, rather than fight in the tackle so that they can get a quick play of the ball away. Our props are pretty good at falling on their stomach.
On defence guys like Lowrie, Friend,
Taylor and Henry are simply not strong enough to consistently put a guy like Kasiano on his back. They are giving away 20-30kgs, and usually just trying to chop him low if they are first there, which makes for a better tackle but a quicker play of the ball.