> I can't imagine upgrading from 1070 to 2070
You're not getting what I'm saying - people stay in the same tier when they upgrade. They might do every generation, every other generation, skip every two generations, but the point is that people who have xx70 (or xx80) will buy xx70 (or xx80) from a newer generation.
10xx to 20xx upgrade made little sense to most gamers because RTX was a thing you turn on, look at pretty reflections and turn off to regain the performance. 10xx generation was a weird generation for NVIDIA and doubt they would make such a consumer friendly generation ever again.