that's 75 weeks' supply of toilet rolls for that family, or 1.5 years worth.

Well, Yes. In normal times, but COVID-19 - by its nature - demands higher usage, and more often. Say 3 times more. 1.5 years looks more like 0.5. And overstocking is insurance, ie redundancy in the original etymological meaning, not the JIT/kanban of modern thinking.

I'm not condoning it, but people are resourceful (& lazy), so the philosophy is: hoard toilet rolls first. Think of alternatives when supplies are gone.

I remember an example of East German humour in the Soviet era of shortages. Picture a man trying to snatch a toilet roll from a taller man holding it a loft. "Give it to me, I need it" - "Why should I? I have only just had it laundered!"