This graph was put together by member dbz at beyond3D forums. Light blue is AMD. Dark blue is Nvidia. It's hard to believe ATI was actually in the lead back in 04. They made the best cards for a year or two with the X800s and x1900s. Then the permanent divide started with the massive failure of the ATI 2900 and the huge success of the Nvidia 8800GT. AMD's last and perhaps final mistake was not having anything to compete with the 970 and 980. If things don't turn around with the R9 300s I suspect they'll have to ditch the discrete GPU market all together. I'm not sure how to make the picture bigger. Here is a link to it. http://i.imgur.com/zkuaRST.png
AMD never really recovered from the double whammy of the Core 2 and Geforce 8800 being released right when they were merging with ATI. Two of the most revolutionary computing products of all time came out right when they were busy with a merger. The Core 2 was probably the biggest leap forward in CPU technology of all time. It was an even bigger leap than the Pentium or Pentium 3, and those were big jumps. The Core architecture instantly made all other CPUs obsolete, was about 6-8x as fast as the Pentium 4s and Ds people were using at the time, and ushered in a new age of computing. The Core 2 was so powerful for its day that it's still a perfectly respectable CPU even now almost 10 years later, and there are still plenty of folks rocking Core 2 Quad Q6600s to this day. The Geforce 8800 was probably the biggest leap forward since the maybe the Radeon 9700 Pro or the original Geforce. It was the first PC GPU with unified shaders. They had no answer for either product for several years, and their answers were lame. The Phenom and 2900XT were big flops when they came out. By then, all but the most diehard of fans had moved on to Intel and nVidia. Their video cards have gotten better from the 4800 series on, and they've won some people back, but they're still way behind nVidia. They're pretty much dead in the water as far as CPUs go. There was some hype surrounding bulldozer as an answer to the i7, but it turned out to be a slow, hot, power guzzling turd. Their APUs make good HTPC chips, but I can't believe there's much money in that. 390X needs to be astounding or AMD is probably finished. I don't think they can survive another Phenom, Bulldozer, or Radeon 2900XT type of failure at this point. I hope they stay afloat because Intel and especially nVidia turn into total dicks when they have no competition. I'm not a fan of the new normal of high-end GPUs costing $550-1000 now that nVidia doesn't have much competition.
In some ways AMD seems to be successful. They power the XboxOne, the PS4, and the next Nintendo. They've cornered the console market but that doesn't seem to help them much. DirectX 12 is the future of PC gaming and it's basically AMDs Mantle design. I think one person said the problem with AMD is they've spread themselves too thin. They're a jack-of-all trades and master of none. I think that could be why they've invested so much into their APU line. It's a niche that didn't have much competition. I'm worried that if AMD totally fails with their GPUs PC gaming may disappear. With AMD gone I expect we'll see Nvidia selling $600 entry level cards and $1000 enthusiast cards. Less people will build gaming machines and game publishers will lose interest in selling to such a tiny market.
I don't think anything that extreme would happen. nVidia has had 70%+ market share for a long time. PC gaming is more popular than ever. Steam has a much bigger following than any game console. None of that's going away, and any time people thought PC gaming was going to die, they've been proven dead wrong. I think more likely what will happen is a continuation of what's going on now with $200 basically being entry level, $350 being midrange, and $550+ being high-end. Which is unfortunate because when nVidia had more competition, you could get performance midrange cards like the 8800GT and GTX 460 that got you close to the high-end cards for $200. But we haven't seen a powerful and affordable card like that for a long time. I hope the 390X succeeds, but the delays have me very worried. When AMD starts heavily delaying things, they usually have a turd on their hands. Phenom, Bulldozer, and the 2900XT were all heavily delayed. The immediate jump to water cooling is also very worrying. What I suspect is that they have a card with very expensive memory hindered by an old architecture that maybe matches the GTX 980 in performance, but does it while running scorching hot and needing water cooling not to roast itself, and is also coming out almost a year later. I'd actually say that's the most likely scenario given AMD's history.
I think the delays have been for two reasons. Them putting more resources into their APU line and a shortage of HBM memory. Originally we thought we'd see 8GB of HBM but now it seems 4GB is the limit. If they believe the HBM cards are their salvation they may be trying to make enough to get a good launch.
Back when I was shopping for iMac I noticed all the new systems were using AMD graphics. Now it looks like the MacBook Pro are switching to AMD as well. http://arstechnica.com/apple/2015/05/apple-announces-new-15-inch-macbook-pro-with-force-touch-and-other-upgrades/
What about the R9 290? It runs a little warm and sucks a bit of power (like the 8800GT and GTX 460), but performs brilliantly for between $200-300.
The 290 took the price/performance crown late in it's life but most people didn't notice. Right now you can grab a 290 for $235 and a 290X for $270. Those might be great prices if the 390X MSRP is over $400.