The first and last time NVIDIA GPUs were worth $1000+ was when the GTX 690 was released. That was 7 years ago even before the first Titan cards surfaced. In fact, it was the pinky toe in the proverbial high price swimming pool for NVIDIA, the card that started this upward trend. The difference between that card and the RTX series is that the price vs performance for the new RTX line is a joke by comparison.
My 690 GTX is still running strong in my son's PC, the same PC I built back in 2012. He is able to play every game out there, maybe not at ultra high settings but definitely not at low settings. The performance level of the 690 is between the 1060 and 1070 performance wise. When was the last time a GPU lasted 7 years?
When built a new system for myself in 2017 I jumped on the 1080 non-ti version as it had the best price vs performance at the time. Purchased through EVGA when they went on sale just before the 1080ti release and less than 3 months after purchasing the ti variant came out I was able to upgrade for only $100. A magnificent deal.
I blame AMD, personally. NVIDIA is only doing what every company has done in similar situations. AMD's latest GPU release in Jan was lackluster, again missing the mark for top tier performance. AMD needs to make NVIDIA sweat like they are making Intel sweat on the CPU side of the house. Competition will make prices come down eventually, but only if there "is" competition. Till then I'll just hang onto my 1080ti. Maybe down the road when AMD truly challenges NVIDIA I'll consider retiring the 690 and handing down my 1080ti to my son.