The other big difference is what's obsessively measured.

A few yards makes a huge difference in rugby, and players are certainly highly incentivised to give it their all, but even for the battering ram-type players, their ability to help the team actually get the ball across the gain line is a function of the stamina and mobility to get around the pitch for multiple phases of play, complex situational awareness and some degree of ball handling skills, not just the ability to block off the man directly in front of them for a few plays.

Not to mention rugby's increasingly strictly applied and penalised rules on what is and isn't a legal tackle which mean that a player who doesn't tackle in a relatively safe manner will be a liability to their teammates as well as themselves