Concurring with several people on this thread we know that many branded items are sold with good reason to expect consumers to pay more for them whilst simple items like lettuces are more generic and can be purchased elsewhere.
We also know that people will pay a premium for the kudos of a brand itself and that a sparkling wine from a plot of land 1 metre outside the legally designated Champagne region can be as good as champers but can't attract that nomenclature. (The Russians refuse to ignore such internationally recognised diktats and sell pomagne to their citizens at a £1 or so a pop).
At the end of the day, we are free to source alternatives to major brands and have the nous to evaluate when it's sensible to do so.
Taxing expensive brands unduly is a recipe bfor disaster (pun intended).