People are in shock. Shock doesn't last two months. And don't forget all the people you don't see at the supermarkets.

As long as shelves remain empty, people will panic. You can not be panicked, see other people panicking, and then become panicked yourself. So it's going to be difficult for supermarkets to reverse what's happened unless they implement quantity limits.

The shelves are only empty because everyone is stockpiling at the same time. There are no food or toiler paper shortages. But the toilet paper truck doesn't come every 2 hours, so if people buy up all the stock they need to wait until the next regularly scheduled shipment arrives.

It's really not much of a problem, beyond the problem people have created by stockpiling too aggressively.