Looking at the numbers from the Digital Foundry video, the 3080 is on average 70% faster in plain raster performance than the 2080. The 2080 is on average 30% slower than the 2080ti, which puts the 3080 at around 40% faster than the 2080ti without raytracing or DLSS.

That's a pretty decent jump, but if you assume that the 3090 will be around 20% faster than that, you've got a card that's roughly 60% faster than the 2080ti and that's before you turn on raytracing or DLSS. That's a massive jump.

The 2080ti was definitely overpriced, but it's no slouch. I've been able to play most games at or very near to 4K at max settings for the past 2 years. A 60% jump in performance, to me, is huge.