We already do have to worry about quantum effects. Electron tunneling is a real concern and one of the causes of chip degradation over operating lifetime. Essen

We already do have to worry about quantum effects. Electron tunneling is a real concern and one of the causes of chip degradation over operating lifetime. Essentially, an excited electron can jump across the transistor gate oxide and get trapped in the gate metal. If this happens enough, the threshhold voltage of the transistor increases, making it slower.