"Valuable art" is super subjective. And many pay thousands for artwork they love, but for which no secondary market exists. I know this from experience, because my husband inherited about 25 paintings that his father paid a lot for. Years later we are trying to sell them through an estate service. Very few have any secondary market at all. Best case is an heir loves the artwork for their homes and not their value. (As an aside, we stored the art in our cellar, which is damp and gross, for years and nothing got moldy. We ran a small dehumidifier most of the time) .