Do you now owe the government the difference in sales tax on the market price of a pre-assembled sandwich versus on the market price of the individual bread, meat, and cheese?
Is it "fair" to owe the government the incremental sandwich sales tax? Should someone who can buy separate bread, meat, and cheese ingredients get such marginal sales tax benefits relative to someone who only can buy pre-made sandwiches? Or does owning the bread, meat, and cheese mean that whatever marginal value you extract from the ingredients' use is fully yours?
Supporting imputed rent seems consistent with supporting my hypothetical sandwich marginal sales tax. It's ridiculous.