What everyone else said, but especially, they shipped in boxes designed for them, with thick styrofoam designed for them, and typically in a plastic bag so when

What everyone else said, but especially, they shipped in boxes designed for them, with thick styrofoam designed for them, and typically in a plastic bag so when styrofoam flaked off, it wouldn't attach to the monitor. New plastic would take a couple bumps without showing anything, but a properly packed box will transfer mostly all the forces it experiences through the box and not to its contents. Tight fitting foam with reinforced corners prevents internal movement of the monitor. There's risk of getting the sides poked in with a fork lift, but when that happens, the damage is obvious and the recipient will refuse delivery if the carrier tries. You can reinforce the faces of the box too, but monitors weren't valuable enough for that.