My many pairs of shoes with only the right big toe blown out tells me I drag my foot. I never notice doing it. It is common for players in the sports of tennis and baseball, too. I don't recall any discussion about well paid Pro sports coaches trying to free athletes of foot drag but maybe they just didn't call me when they were discussing it.
At least some of the toe wear happens during the push-off, which starts before release. On my forehand drive ( I think generally forehanders have more wear on their toes than backhanders), my non-plant foot starts with the ball of the foot in contact with the tee pad/surface then rotates toward the side of the big toe then to the top of the big toe during the follow through.
I know sometimes my non-plant foot slips out during the drive with loss of power and control. So the push-off part of the drive adds power, rather than diminishing it.
The toe push-off continues during the hit and does not stop there but continues, aiding body motion in the follow through. Toe drag probably creates some friction during the follow through slowing the non-plant leg down a bit, more so during the end of the follow through. The leg slowing down a bit shouldn't slow down the throwing arm until the very end of the follow through, should it? Where is our ultra high speed video camera??
But say the friction did slow or restrict the follow through. What impact would it have on the shot? Would a faster follow through lead to more distance?? And how much more based on an incremental change? Chuck Kennedy probably has several scientific theories that might apply.
Leave the mechanics a moment and consider the mental aspect of making this change. The instant of release is critical to every shot. But that instant would have to be when we focused on picking up our non-plant foot to avoid the foot drag. If we waited until after release to worry about foot drag then it would too late. I guess if we can train fleas to do tricks in mini circuses we could eventually train ourselves to instinctively pick a foot during the follow through.
It would be a real hassle if the shoe manufacturers picketed my home in protest to my giving up foot dragging, which has enriched their profit margin all these years.
Could be that your center of gravity is closer to your back foot during your pull-through. Getting that C.O.G. right over your plant foot at the moment of release and in in front of your plant foot immediately thereafter should force a better rotation, which would force foot off the ground.
I doubt that foot-drag itself has much of an impact on your throw...but it might be a product of something else that IS affecting your throw.