I am sure some people do buy Titan series for prosumer applications but the recent Titan X was really a low blow - NV basically took a consumer GM200 and doubled its VRAM and we got a $550 GTX580 3GB successor for $1000. Rest assured there is a market of PC gamers who want to buy the best whether it's labelled the Titan or not. I am actually surprised NV hasn't raised the price of the Titan to $1300-1500. It seems that many Titan X owners like the idea of knowing their card costs the most and it's the fastest so I think NV still hasn't quite reached the peak of the Titan brand's potential. If next generation they add back DP and go 32GB of HBM2, I can see them going to $1300-1500. Wouldn't you if you knew that the TX customers would still buy them?
Bad comparison, 580s were already "Titan's" on their own accord, DP perf was never crippled on those (and thats why you had the low gaming perf-watt on GF110), so even a 580 3GB was a steal for the prosumer compared to the Titan, not even talking about Titan X, which is as crippled in DP capabilites as the 980 Ti, and only has double the VRAM.