Millennial's don't seem to hate mayo, they just seem to prefer dressed up mayo. Throw some garlic, sriracha, lemon, or avocado in it and you can sell it for 2 dollars an ounce to accompany some parmesan, duck fat, truffle fries for 12 dollars.
Not that I'm judging, the growth in the variety and options in unique gastronomy is at a peak it feels.