> what about just dragging a long distance where you would normally lift the mouse or finger?

This is why you set Trackpad speed to "fastest", and take advantage of the aggressive trackpad acceleration. When you move your finger quickly you'll easily reach the far side of the screen before your finger reaches the edge of the pad, and slow finger movements will still be precise

I'm probably missing some context, but on my Mac I'm using three fingers drag and I can lift fingers and (quickly) reposition them without breaking the drag.

This reminded me of a feature in windows where if you were dragging something and reached the end of the touchpad, the cursor would continue on the same trajectory as long as you kept your finger at the edge of the touchpad. Then you could overshoot a little so you could bring your fingers back to the middle to regain maneuverability. I haven't missed it since I switched to linux but now that I'm thinking about it that was a very nice touch (no pun intended).