Have also seen data showing declines almost every year during Nov-Dec following peaks in July-Aug-early Sept. That's the normal cycle of loading up on holiday sales inventory then selling it off. This year's numbers have kind of exaggerated and rescheduled that due to the trade war and tariffs.

As for the wine shop loading up on French wine: will the owner keep the prices down based on what he paid, or raise them to what the competitors impacted by the tariff are doing (meaning more profit)? Situation similar to gasoline prices - they always go up quicker than they go down: the value of the gas in storage at the station rises as fast as the wholesale price regardless of what was paid for it, meaning so does the pump price, but when the wholesale price drops the gas in storage still has the value that was paid for it, so pump price stays high until well after new deliveries have lowered the value of what's in the tanks again. Plus, profit. Same thing with wine I'm sure. But there might a sale in January when the owner discovers what all that extra inventory means for the tax bill...