I do not know how you got the average increases:
In traditional rasterisation the RTX 2080ti on average is faster than the GTX 1080ti by 37 % on 2160p Ultra, more is expected on the long run with additional releases of AAA titles and as more drivers will be tweaked after initial lunch . It kills the GTX 1080ti on 2160p Ultra without compromises at above 60fps performance. That is a great leap indeed in modern AAA titles that the GTX 1080ti failed to have a constant 60fps experience with a lot of dips. To me it is a definite upgrade.
Here comes DLSS that greatly widen the gap with above 50 % gains on supported DLSS titles ( 29 Till now)
Anandtech:
"and the RTX 2080 Ti would be offering 37%"
Concerning the price , it is a lunch price and prices will normalize after lunch. Remember , new technology always costs especially with high prices of current V-Ram/Ram models, the TU 102 in the RTX 2080ti contains 18.9 billion transistors in 752 mm2 die size and that includes three discrete processors: the Turing SM, the RT Core, and the Tensor Core compared to GP 102 in the 1080ti that contains 14 billion transistor with a die size of 471 mm2.
Turing offers Real time ray tracing to the end customer which needs a lot of computational power and established a new foundation of rendering away from regular rasterization rendering. That is not possible before at all and require 3 V100 Graphic cards working to render real time ray tracing.
Giving a generalization / or assumption on alpha/beta testing of RT is objective, MS will role their Windows 10 RT Direct 12 API in October along with Nvidia mature drivers and patches of RT in released games that support it ( Shadow Tomb Raider now). ‘Tomb Raider’ devs respond to RTX 2080 Ti, ray tracing performance concerns /
https://www.digitaltrends.com/computing/tomb-raider-dev-responds-to-rtx-2080-ti-performance-concerns/ - People like to bash a lot about new tech since in expensive in already expensive environment. To me I do not care about money in evolving tech to assure my max game-play needs / satisfaction on AAA titles and online demanding titles - 2160p Ultra with no compromises and multiplayer - 100hz locked on 3440 *1440p and 200hz locked on 3440*1440p @ 200hz at the upcoming PG 35VQ which I will drop and replace my current PG 348Q.