Imagine that 10 normal people and Bill Gates want to buy bottles of wine. Bill goes for a bottle of $6000 Richebourg Grand Cru, and the 10 normal people always go for Shitscreek Red, sold for $4. So about 9% of the buyers are willing to pay extra for the name brand.
After the Great Wine Tax Bill of 2021, the prices are both increased by a fixed per-bottle amount of $6000. So now the Richebourg costs $12000, and the Shitscreek costs $6004. The 10 normal people migrate to beer, and Bill Gates still buys Richebourg. So about 100% of the buyers are willing to pay extra for the name brand.