Evidently the first people feathred (the ones canning everything in sight) who thought the Earth Plates would shift have never been in an earthquake. They had no safety straps running the length of their shelves to hold the jars etc. on the shelves to keep them from falling on the floor. After the first few seconds of shaking, all their goods in glass would be broken and useless.
Bugging out as they did with busses and cars is fine with no other traffic on the road but in a real emergency, they probably wouldn't be able to move any distance in any acceptable time.