Take another look. That's not what its saying when comparing 2080 vs 1080. It's more like around 1.5. When tensor cores are used vs no tensor cores they are saying it's 2.0x.
And look at the HDR results LOL. Besides, the community said time and time again to take manufacture performance charts with a grain of salt.
Uhh, 1.5 is 50% increase. Not sure what you are on about. I've never found the NVIDIA performance slides that far off in the past.