Except that Rakata should be compared to Battlemaster (58 v 58) while War Hero should be compared to Black Hole or Campaign (61 v 61).
I'm willing to bet there are faaar more players with full War Hero than with full Black Hole/Campaign.
There's a very simple reason for this: lockouts. You can only raid for gear once per week. Yeah, there's the random daily through the group finder and other methods to get BH comms, but they've effectively limited the amount of PvE gear one can get through the system. In PvP, it's just a matter of how much time you can commit to it.