Asked about the raw gaming performance in current games, Nvidia's Director of Technical Marketing Tom Petersen stated that the new RTX 2000 GPUs are between 355 and 45% faster than the Pascal cards. However, upcoming games may perform better if they are specifically coded to take advantage of the new Turing Tensor cores that facilitate the DLSS tech.
https://www.notebookcheck.net/Nvidia-official-says-the-RTX-20xx-cards-are-at-best-45-faster-than-the-Pascal-counterparts.328192.0.html
It's going to be interesting when we take AA out of the equation entirely just how much faster the new chips are. At 27-32" 4k doesn't really need AA. It just needs pixel throughput. That is for most buyers, the real number they care about. If it doesn't deliver, and cost effectively, then potential buyers will ignore the new chips.
IMO if you were gonna buy a high end graphics card anyway then being able to run the latest effects i.e. ray tracing matters.
Also I don't suppose a 1080 could match a 2070 in efficiency or low pricing even though performance could match?