Wayne Thiebaud’s earlier information at public sale, together with the $19.1 million achieved in 2020 for “Four Pinball Machines,” illustrate the enduring attraction of his work. The sale of “Candy Counter” for $12.5 million in May 2023, nicely above its estimate, additional demonstrates the strong demand for his art. The painting, which has been stored privately for over 50 years, comes from the gathering of Morton and Estelle Sosland, devoted art patrons from Kansas City who handed away in 2019 and 2021. The Soslands acquired “Avocado Salad” directly from Allan Stone, Thiebaud’s first New York gallerist within the late 1960s.…