An Nvidia 3070 costs 420 and benchmarks at 22,403 (benchmark point per dollar 53.34)
An AMD 6800 costs 360 and benchmarks at 22,309 (benchmark point per dollar 61.97)
So you get a 0.4% drop in performance for a 14.3% drop in price. That is significantly more performance per dollar.
Or if you go with a 3070ti ($500 23,661 -> 47.32) vs a 7800 XT ($500 23,998 -> 47.97) you get a 1.4% performance increase for free (not really that significant I know, but still it's free performance)