A husband and wife spent six years and over $650,000 trying to sell America a slice of ketchup. They got a deal on Shark Tank in 2021. Their company was dead within eight months. Hellmann's just shipped the same product, and it's stocked at Walmart and Target. The idea wasn't even theirs. A chef named Ernesto Uchimura invented "ketchup leather" at an LA burger spot in 2015 to stop buns from going soggy. The internet ridiculed it as food hackery, a solution to a problem nobody had. Cole and…