When I started my career with private label products were always cheaper with worse quality. Consumer knows that choosing this product can save money at the expense of quality. Producer or store chains could raise up your marge because marketing was unnecessary but it was a many, many times ago. Actually, I am old man :) Nowadays, change almost everything. Private label products don't mean worse products and sometimes need a serious marketing campaign. It's because market is full with a many of competitors.
Example from Poland - one of the supermarket chain's W5 has become one of the most popular product among a wide range of similar products, including big brands.
In your experience, what categories have seen the most dramatic transformation from "budget private label" to "premium private label," and what factors drove this evolution most successfully?