In thinking further about it (and staying on topic
), I'll bet it won't be long before cup/stick manufacturers come up with a design similar (lighter and curled on the edges, so it won't mark the greens when laid down?) to what is used on most putting greens so that the flagstick has a base on it...thereby making it easier to pull the ball out of the hole by pulling out the flagstick.
In fact, having a broader base might also help keep the flag straighter when the wind is blowing and/or...when the cup is not cut perfectly.
Soooo, never mind about inventing a device for the end of the grip to pull the ball out with the stick in.
Gee, I just saved myself...a whole lot of cerebral work.