Having been in the automotive field (doesn't make me an expert), I would guess that Mitsubishi would not discontinue the *CURRENT* Mirage in the U.S. / North America until regulations may force it out.
What would seem more logical (to me) is that Mitsubishi would limp the current model along until it dies of natural causes or it is regulated out. I say that because the minor model change of the 2021 just cost Mitsubishi a fair amount of money. Most auto companies amortize cost recovery on a 3 year basis. That's not to say they don't make their money back sooner than that, but that's how they count the beans ... typically.
And since electric vehicles are on their way to ruin everything, why develop a whole new gas model Mirage? The current model will be amortized completely soon, why not just keep producing it and stacking paper until it is just not viable any longer? I surmise, I could be wrong. I'm still on the band wagon that a pure electric vehicle blows. But a hybrid (especially like the Volt) is far superior. The
benefits of the electric vehicle with the advantages of the gas vehicle to overcome the obstacle(s) of the electric vehicle.
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View my fuel log 2020 Mirage ES 1.2 manual: 42.5 mpg (US) ... 18.1 km/L ... 5.5 L/100 km ... 51.0 mpg (Imp)