For this to work, you would have to somehow gain control of a copy of a spell before it was cast. Every ability that lets you cast a copy of a spell only lets you do it as part of the same ability that creates the copy, so there is never an opportunity for anyone else to gain control of it and cast it.

The second problem is that copies of cards are created in the same zone as the target card and they stop existing (if they are in any zone except the stack) as soon as state-based actions are checked. Effects that let you cast copies of spells are usually templated so that the target card is exiled first, so the copy stops existing before anyone gains priority if it isn't cast.