Why is it so hard for people to understand that Enthusiast and High End cards make about of 5% of total GPU sales. That's a luxury market. Both AMD and Nvidia make a about 80% of their GPU profits on laptop, OEM, low-end and mid-range discreet cards.
This is what AMD is targeting with Polaris. It doesn't matter that it can't compete with the GTX 1080 or possibly the GTX 1070, it was never meant to go head to head with those two. But if one variant of the Polaris 10 chip can deliver performance north of R9 390x/R9 Fury for let's say $200-250 they have already won in that segment, and cut version of Polaris 10 might even go sub $200, and then there's Polaris 11 if they make discreet graphics out of it. Not to mention Apple is already going with Polaris GPUs in their future laptops.
Some tend to forget that people who buy cards for $500+ are in the vast minority. The market is blooming in the $100-$250 range.
Vega was always speculated to hit early Q1 of fiscal 2017, which starts for all companies pretty much in late 2016. It has nothing to do with Nvidia, and AMD starting to panic. It's proceeding as planned, and if they really moved it up, maybe the yields are better for both the chips and HBM2. Naturally AMD also knows that people want enthusiast grade cards, they have not forgot about them, so do AMD AIBs, even tho it doesn't make that much money in the big picture.
People are spelling doom and gloom, when this was never the case, not a single time in history. Both Nvidia and AMD are always neck on neck with their performance in comparable segments, I don't know why this should change now, except if they mess up real badly, but looking at the leaked benchmarks, Polaris is doing just fine for what it was meant to do, so really I don't know why people would worry at all.
Problem is people who don't follow this specific tech industry, don't know that Polaris was never meant as a top card, and they will be disappointed. But that happens all the time anyway, and the Nvidia "fanboys" are always louder, no wonder when they hold ~80% market share, it's to be expected. But at the end of the day, AMD Radeon Group is doing just fine, financial wise as performance wise with their past, current and future cards, no doubt about it.