Hogan wrote of torque...that comes from the difference between the hips and shoulders at full rotation. Right?
I bet if you looked at the top of the swings you'd see considerably more spread between hip and shoulder rotation in today's players than that Hogan video.
Looks to me like the shoulders rotate about the same and the hips about half as much today...clearly by choice.
I also think if you looked at the same swings at impact the relative rotation would be at least equal today as well...in other words, they're clearing their hips really aggressively after not much rotation away.