Check out the casing stones still left at the top of the Khufu pyramid and then look at how the Step Pyramid's outer layer was built, because that is where the real jump hides. The Step Pyramid got a skin of fine limestone added later to make it look smooth, but it was still sitting on a core of small stacked blocks. Giza was planned from day one as a true pyramid with big blocks locked together the whole way through, not a stack that got dressed up after. That tells me the change was not just about size, it was about building the thing as one solid piece from the start. Dig reports keep arguing about which site came first, but the real question is who figured out you could design the whole shape up front instead of adding to it. Look at Meidum too, that one sits right in the messy middle and nobody wants to touch it because it fell apart.

Same at my kid's school, teacher can't even tell the difference anymore.