The thing is these are planned years in advance.
Normally 4080 series cards are only 20% or so slower than the 4090 cards, so AMD aiming to be better than the 4080 makes sense not quite 4090 level but close enough to be between the expected 4080 specs and the 4090, this would match up with AMDs claims 1.5 - 1.7x performance would put it around 10-20% slower than the 4090 roughtly where the 4080 should sit, this would also match AMD's price, $200 cheaper than the 4080 for roughly the same performance or better (less the obvious weaker RT performance). The problem is Nvidia royally scewed themselves over by having the 4080 60% of the 4090 rather than the usual 80% based on past releases, AMD likely expected the 4080 to be 80% of the 4090 spec thus aimed for that mark, the problem is Nvidia gambled their hand and lost, this makes the 4080 way less valuable than the AMD competition.
Of course we will need to see the final reviews, but i do expect the 7900xtx to be comfortably better than the 4080 in normal performance, RT is up in the air, i think the 4080 will be roughtly 3090ti RT performance or a tad better but not by a significant margin.