Remember AMD isn't just releasing one SKU of BigNavi, but three. There isn't much room regarding performance between 3080 10GB and 3090, so if Navi21XTX performs slightly above 3080, there isn't much they can do about it, 3080 20GB wouldn't add much to performance atm, but cost much more, while a 3080Ti/S with more SM (up to 72 or 6 full GPC, like the rumored GA103 ist going to have) will kill both the 3080 and 3090.
But if Navi21XT performs much better than 3070 and the canceled 3070Ti, they can at least counter that with this GPU, albeit the profitmargin will be quite bad. It will be better, if this SKU will use the GA103 later on, like the 3080, but even then it isn't what NV would wish for. But that's what happened last year with 2060S and 2070S, which werre essentially 2070 and 2080 with some SM deactivated, but with the same PCB and same cost for a lower price, just to counter RX 5700(XT).
What I don't understand ist how NV hopes to keep their market share by offering three SKUs based on the same chip when they already said they can't offer enough chips for one this year.
The coming weeks will be exciting, it's still everything possible. Looks like Navi21XTX can outpferform a 3080