I thought the long term trend has shown for a long time the size of chip components converging to the size of an atom by the late teens. A little hard to imagine how physical transistors can get smaller than that. Possibly qubits could built from smaller particles: photons, electrons
We could still get speed ups from higher electron and/or hole mobility after we stop shrinking things by going to different materials, but yeah - that really won't be Moore's law any more.
