I've been saying this for a while. It doesn't make sense to trade talent from the MLB roster or finish gutting their already weak MiLB system just to sign Harper who may not match the level of production they'd be trading away and will probably leave when Bryant leaves anyway because I don't see how they can afford both of them while still remaining competitive (ie paying Rizzo, Baez, Q, Hendricks, etc.)
That's not to say the Cubs aren't trying to do this, but I can't imagine they're going to be successful. And if somehow they manage to swing this I don't see that team being any better than they are right now.