Rexer :
When AMD first introduced 480 with Polaris, it wasn't a chip that was exploitable. I mean, they said you can't clock it past 1250 mhz without a few crashes here and there. With a change in the vbios, they gained a little more clock speed (somewhere @1330 mhz at top end) and cooler, too. Hence the 580.
Now comes the 590 that can reach 1500 mhz on clocks and still run cool. It seems obvious that this was the plan AMD had all along. To build a chip model that can be upgraded year after year with only a vbios flash while being a better, faster same thing. Sort of comparing it to how a car like the VW Beatle existed year after year. It wasn't a thunderous pony car but the same design with small yearly upgrades.
While not saying this is a bad thing since it saves AMD a huge amount of money, I think this was AMD's business game all along. To me, there's no telling how far you can take 7mn Polaris. Each time a new Polaris card is introduced, it's a bit faster and still cool. Kudos to AMD.
The biggest problem to AMD's GPU line right now it is just hasn't had the impact that in the recent year we have begun to look for with AMD. AMD's GPU line needs a Ryzen like competitor. I mean I can truly say that six months after purchasing my R7 2700X and even after Intel released their "9th Gen" processor line that I still have the best overall consumer grade workstation CPU available. I make that based on overall performance and total system build cost. The R7 2700X is even with the newly released i7 9700K in overall productivity while costing much less (especially factoring in the need of aftermarket cooling) and although it is beaten by the i9 9900K the cost of such a system build really places it in the next tier up--> enthusiast workstation build where it would have a much harder time vs Threadripper. Factoring in total system build costs, performance, and power utilization (biggest reflect here is thermals and the need of ever increasing premium after market cooling) I can rightly justify saying I have the best consumer grade workstation processor available today with my Ryzen R7 2700X.
On the GPU side AMD has nothing that can quote the same. The Vega 56 and 64 are generally outperformed by the GTX 1070Ti and 1080Ti and come in with retail pricing that basically is the same. If the Vega 56 costs the same (retail) as the 1070Ti and the Vega 64 costs about the same as the 1080Ti, but the GTX GPUs are using less power, running cooler, and have overall better performance then there is no reason to buy Vega and you can't make an argument for Vega being better. AMD needs a high end winner, not a mid range one. While the RX 590 may be the new king of the mid range it doesn't help anyone looking to upgrade from an already good mid range card.
There are a lot of people like me who have invested in their computers for work related tasks and also happen to game on those systems. My R7 2700X is a rendering and video editing beast, and is just perfect for my productivity needs. I already have an aged R9 290 heavily overclocked that is a very capable 1080p GPU. I would like to upgrade that (and will be shortly to the 1070Ti) but what has AMD released that is worthy? The RX 580, and RX 590 are going to be lateral upgrades that only offer slightly better performance and sure won't get me gaming properly at 2K and 4K resolutions. If I'm going to "upgrade" an already very capable 1080p gaming GPU I want to get my foot in the door of 2K and 4K gaming or its not an upgrade. I want a GPU that can unleash the full power of my amazing processor. AMD has Vega but 56 and 64 are running the same retail costs as the 1070Ti and 1080Ti that not only outperform them in games but use less power and are cooler while doing so. For someone like me (and I know I'm not alone) AMD just really doesn't have that "go to" GPU upgrade that has the performance and value.