There might have been a short-term panic over-buying plus the fact that everybody all of a sudden was staying home (and *ahem*, going to the toilet at home more) as opposed to going to the office. That's just a hypothesis, I haven't looked at any data. But your point is essentially correct, I assume it just takes a bit of time to shift the supply from commercial/business channels (delivering to office buildings in the city) to consumer ones (delivering to stores like Costco, Walmart, etc).