1. The x-factor. Contrary to their claims, chemists and food scientists don't have it figured out. They are only 99% of the way there. It's true that people won't be able to tell the difference, but it is different. This is similar to the science claims that we can make a drink that delivers all our nutritional needs but a pure Soylent diet leaves many people with headaches or cravings. Sometimes the tiny 1% x-factor ends up punching above its weight.
2. Authenticity. Honestly, I like the taste of cheap Japanese blended "scotch" more than any $500 bottle of 23 year old from the highlands. However, that Japanese blend isn't an authentic scotch. I still buy expensive scotch. I want to be able to tell people that my whisky sat in a barrel for decades, using water from a specific river and distilled according to an archaic set of rules. Lab aged whisky, no matter how good, will just be plain whisky and not part of a historic identity. This is similar to people not wanting to buy a lab grown diamond, even though the lab grown diamond is just as pretty and isn't responsible for child soldiers dying in Africa.