A price cut (Slim-$249/Pro-$349) can definitely help keep sales relatively stable through the regular months but it would also make a $199 bundle during the holidays less of a big deal so I agree that its age will definitely start to show.
It will still sell great in 2019, I'm guessing like ~15 million.
Yeah, 15-16M is reasonable with just a 50$ discout. I agree. To reach 16-17M levels it needs a better discount.