Compared to 10xx, not too long. But they just came out.
Sometime between fall and next spring is my guess. Navi should force a refresh if nothing else.
The last few releases have been disappointing.
Vega, expensive and less efficient than 1070/1080, and no flagship speed.
RTX, expensive, low on memory, doesn't compare all that hot $/perf to 10xx AIB and even Vega now that it's cheaper.
Vega 7, $$$$$. Not all bad though, I guess 1080ti perf for $699 w/16GB, though if you can find a 1080ti for less, then that's the win.
Ugh.