D&S Model

Does Economics have any demand and supply model? The question looks superfluous, and the answer should be definitely positive. E.g., there is one in the tax incidence theory, but in which market is such theory applicable? Is it applicable to international trade? No, for import and export are two different products. Can it be applied to the monopoly theory? No, for everyone knows a monopolist has no supply curve, and it does not have to pay attention to consumer’s demand at all. How about the housing market? No, for such market has only a rent gradient function. Perhaps, in the money market? No, Oscar Lange has long maintained that there is no money market. Is the IS-LM model a demand and supply model? No, for its original author has already renounced it. Is the ADAS model a demand and supply model? No, for the aggregation of different products can only be conducted in value, which has no price-quantity relation any more. Does Economics really have a demand and supply model?