The confusion that many people get into is that they think the lower body causes or produces speed.
... arms and hands can move the club faster with proper support from the legs.
Is this not cause and effect? Therefore, does not the lower body contribute to and "cause/produce" speed? If a golfer can hit a driver 200 yds sitting on a chair, couldn't they hit it farther by standing and more effectively using their lower body? (Sitting on a chair does not eliminate the lower body, it merely reduces its effectiveness.) How can you then say that the lower body does not cause/produce speed?
We've had this discussion on the forum quite awhile ago, but conservation of angular momentum generates club head speed, like a whip. Shortening the whip will reduce the amount of speed that can be generated. Unfortunately, we cannot disconnect the human body parts to prove which piece is the major contributor, but disabling the legs is like removing the base of a whip which will result in a major loss of speed.