I like your appraisal, especially "something not bought = something not produced". But I don't understand your final paragraph. How does the situation change if you replace an old but good winter coat in the winter rather than the summer? The season in which you buy something seems irrelevant to me.
If it ultimately doesn't sell, that's a signal to the manufacturer that will affect forecasting and production next year. Manufacturers don't want to waste money manufacturing things that don't end up selling.
