I'm 98% sure this is a lie told by marketing agencies who base it on biased research.

Rearranging a store means closing it for often days, investing in additional staff hours, contractors, etc., having the staff work slower for the next week until they get the hang of the new structure.

And the result is two people buying a pack of butter more during the next week?

And think about it, that scheme only works for customers who already know the store. So they're regulars. If they buy more butter this week, they'll buy less butter next week - because they still have butter.