This is the hole that AMD stucked in...on one hand the sensible people are wishing AMD to deliver the 390x that can compete with the Titan X at nearly half the price, on the other people are queuing up to buy the Titan X...so even if both the 390x shift the same volume at say 2/3 of Titan X's price, their profit margin still won't match those of Nvidia's.
It is an unfair battleground, AMD can have the same upper-hand as Nvidia, but still struggle to shift cards just because they are not Nvidia (remember how 7950/7970 was launched before the 680 to compete with the GTX580, and it still couldn't shift healthy volume despite being faster? Now Nvidia is doing the same with their 970/980 against AMD's 290/290x, and they are flying off the shelves).
If AMD was to have another bout with Nvidia again similar to the AMD 200 series vs Nvidia 700 series situation, it isn't going to improve AMD's market situation (actually it would be worse this time round without the mining craze). The only way that AMD can dig themself out of that hole and actually win back the market share is to bring out a card that is so fast, that it utter humiliate and defeat the Titan X by a ridiculous large margin, burying it so deep in the sand that it doesn't see the light of day...like how the HD5000 series was, leaving Nvidia to catch up. If there's enough Nvidia buyer remorse, and they might start looking at AMD again rather than having the eyes and mind glued to Nvidia.