Of course they don't because they aren't good enough to game at 1080p. If they were good enough so many people would buy them. I would buy one and use that as a travel computer. Can you image how small and relatively cheap a gaming computer could be with such a powerful iGPU.
I can imagine it being small but there's no way that they'd sell it for cheap. The fact is that AMD isn't going to have ATi make an IGP that makes people want to buy their cards less and there's no way that an IGP will ever be able to match a discrete GPU in performance just like a prop-driven plane will never be able to match a jet. It's just the nature of the thing.
I would point out that if you want to game on a craptop, 1080p isn't important. Craptop screens (
especially the smaller ones) look exactly the same at 720p as they do at 1080p. When I'm watching something on my ASUS VivoBook (which has a 15.6" 1080p screen), I really can't tell the difference between 720p and 1080p because the screen's too small to do so. This is why I crack up when I hear people talking about their 1080p or 1440p phones.
The only reason why we came up with resolutions like 1080p, 1440p and 2160p is because screens were getting larger and the larger a screen is, the more that pixellation will be amplified at lower resolutions. Try gaming with your craptop at 720p and you'll be pleasantly surprised to see that you get the same experience and it's far less of a strain on your IGP.
Hell, I managed to run Skyrim at 720p with medium settings on my old AMD A8-3500M-based Acer Aspire and it was playable. I didn't continue with it because I just wanted to experiment but if the old HD 6620G IGP that came with the Llano A8-3500M could play Skyrim decently at 720p medium, then a Vega-based IGP should have little difficulty doing the same with modern titles.
What AMD currently puts out is "good enough" that there's not much demand for something better, at least, not enough for them to prioritise it over other things. If I were Lisa Su (please don't try to visualise that...lol), with everything else that's going on, it would be the furthest thing from my mind. Hell, TSMC can't even meet the demand that currently exists. I don't think that adding to their plate would make things any better.
Now, don't get me wrong, if ATi created an IGP that was based on RDNA, I would LOVE it! It would be a wonderful thing and I wasn't saying that you're wrong about that because you're not. I was only explaining
why AMD wasn't going to do it anytime soon. Hey, believe me, sentiment-wise, I'm 100% with you on getting an RDNA-based IGP released.