Product launches, 3 of them in as many months. New driver for each one. A new driver came out the day before 3080 launch, a few days after 3090 launch, and again the day of 3070 launch.
And there is still one more to go for this first batch, though Nvidia is keeping mum about it up till now. Nvidia will almost CERTAINLY release it the day Radeon 6000 becomes available to buy. That driver is a cruel one though, it's been sat on by Nvidia awaiting AMD's launch.
The point is Nvidia has approximately ~10% at the highest end untapped intentionally. That number drops as model levels go down the list. 3090 has about 10% untapped, 3080 7%, and 3070 might sneak out a 5% improvement. It's not a KILLER performance driver like the old days, but is still a nice bump coming. All locked away at the driver level.