They pushed ray tracing as the big differentiator but it's made marginal difference to graphics quality and has a performance overhead that really doesn't justify the difference.
Add to that the modest improvements in more traditional graphics performance, the multiple variants of multiple families of cards confusing things and the high prices relative to AMD graphics cards, and it's not a surprise they're getting fewer gaming sales than last year.
I'm still using a 2016 PC for gaming that's coping perfectly well with the latest games (albeit I haven't tried Red Dead Redemption) so the pressure to upgrade just isn't there. When I do need to make a change, I may ditch nvidia for the first time in 15 years. They need to do better to compete; price, performance and power all factor in, and they can't rely any more on the ATI driver issues that helped them create their early market dominance.