Just thinking out-loud...
I wonder if a weak supply of 2020 Mirages (possibly due to COVID-related plant shutdowns early last year) may have negatively impacted 2020 sales.
Based on what I was seeing at my local dealers and surfing dealer websites, it seemed like shipments of new 2020s stopped at some point in the year...maybe earlier than usual. Dealers didn't seem to have a huge supply of 2020 Mirages going into the 4th quarter. You would expect to see a lot of leftover 2020s right now, but that's not what I'm seeing locally. White Bear (who typically has 75+ Mirages in stock) only has 36 in stock right now...and only 8 are 2020 models.
I also noticed that Mirage rebates in 2020 generally weren't that great. Maybe that was a result of a lack of supply? Why discount a 2020 if dealer stock is already low there's nothing coming in to replace them?
I did notice that the first 2021s are finally showing up at my local dealers.
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View my fuel log 2015 Mirage ES 1.2 manual: 52.2 mpg (US) ... 22.2 km/L ... 4.5 L/100 km ... 62.6 mpg (Imp)