Which items are sold out and described as panic-buying does seem to vary. I think you may be right about slight fluctuations in buying patterns having a much bigger impact overall, and the sensivities about supply chains, especially with the move, over decades now, to just in time systems. The buying and distributing systems in supermarkets, especially, are dynamic and very sensitive with constant data inputting. In the eighties, there was the move to ordering at the end of day the supplies that would be delivered in the morning. Previously supermarkets held a week's worth of non-perishable stocks and ordered perishables three times a week (the latter was considered a gross infringement by staff at the time). The cycle will be shorter now, especially with the development of huge distribution centres (acres, if not miles, of them) in the Midlands.
These may offer some insights:
Future of UK Wholesaling 2019
Grocery Retail Trends 2019
But I guess, at the end of the day, part of our psyche does love drama :)