Evidence?
That AMD seemed to want to compete with the 1660ti and not the 1660super.
If they had put out the lower power/clocked 5600xt at $250 and the high power at $280-300 they'd be competitive or better in most cases. The 1660ti was effectively dead once the 1660super came out. The 2060 was dead when the 5700 came out last summer, especially when the custom cards released. Nvidia keeping the 2060 at $350 earned them a lot of scorn and laughs. Now they're laughing and the new KO is apparently good for some workstation programs.
Now we have a 5600XT that is $280-300+ that is moving in on 5700 territory. If I'm spending $300+ on a card, I'm thinking 5700 offers more at 8gb of ram and a 256bit bus, longevity wise. Performance/price wise, well the 5700 is not looking so hot now. Its just the same old story we had last year from Nvidia. Stagnation and a way to upsell customers on buying more card for more money. Looking at the DF video linked they made a pretty compelling case for just going with a 1660Super at $230-250 for most games.
Yay, 1080p ultra with less or equal ram for the same prices as 2016/17 cards. Cards that you can still buy new for $150 or $100 used. Any of the new touted techs aren't that much of a seller IMO.