I think they'll be happy to miss that target. 2018 sales for the GT-R = 538 (2017 = 578). You hardly see one on the road. Base price is somewhere around $110k. Great car or not, I think only small exotic-car companies would label 538 units as a good year. Like most automakers, Toyota isn't in the business just to prove they can impress - they're where they are because they sell vehicles. From what I've seen, the Supra will be in the $50k - $60k range (unless demand changes that). More folks can afford that, so if the Supra has wide appeal, it should sell.
When Supra sales dropped off to around 1200 annually in the late 90s (more than the past 2 years combined for the GT-R), they turned it off.
Halo cars are never about the numbers. The legendary Supra was a halo car