From Techpowerup 4K Rasterization comparison 7900XTX vs 4080:
Hitman 3: 6.5% faster
Dying Light 2: 7.3% faster
Divinity: Original Sin II: 7.6% faster
Cyberpunk 2077: 8.3% faster
Assassin's Creed Valhalla: 9.4% faster
Battlefield V: 13.9% faster
Watch Dogs: Legion: 15.3% faster
Red Dead Redemption 2: 17.7% faster
Resident Evil: Village: 18.2% faster
Far Cry 6: 21% faster
As for the physical size of of the 4080 play it down as a non-issue in your headcanon all your want, but it reality is that its size
IS something which the users would have to think about when it come to purchasing decision.
- Nvidia Founders Edition: 304 x 137 x 61mm (3-slot)
- ASUS ROG Strix – 357.6 x 149.3 x 70.1mm (4-slot)
- ASUS TUF Gaming – 348.2 x 150 x 72.6 mm (4-slot)
- Colorful iGame Neptune – Card: 253.5 x 170.8 x 41.5mm (2-slot), Radiator: 394 x 119.2 x 54.4mm
- Gainward Phantom GS – 329 x 142 x 70mm (4-slot)
- Galax SG/ KFA2 SG – 352 x 153 x 66mm (3.5-slot)
- MSI Gaming X Trio – 337 x 140 x 67 mm (3.5-slot)
- MSI Suprim X – 336 x 142 x 78 mm (4.5-slot)
- MSI VENTUS 3X – 322 x 136 x 63mm (3-slot)
- PNY XLR8 Gaming Verto Epic-X RGB – 331.7 x 136.9 x 71.1mm (4-slot)
- Zotac AMP Extreme AIRO – 355.5 x 149.6 x 72.1mm (4-slot)
You simply can not generalise and expect everyone to have a full-size/over-sized ATX cases; there are plenty of people with Micro-ATX PC which the length of the card might not necessarily be the issue, but the card being 3-4 slots in height and/or 140-150mm in width is (side-panel clearance issue). Like it or not, the reality is that oversized card will alienate some userbase, and the simply reality is smaller cards WILL fit in more cases than a larger ones- that's just how physics is.