As a big SLI fan I find it a bit disappointing, 2x RTX 3080 would have been perfect this gen, and for the price of single 3090, but guess no cheaping out this time. But this isn't that much of a big deal, SLI was high-end enthusiast thing for years anyway, if you get it now then it is in 99% for already existing games, not future ones. It will now slowly neglect even more than before. But this time it is less because games are made with bare minimum effort and more because it is getting replaced with AI that provides similar gains without requiring second GPU, so it is understandable now more than ever, with software solutions driving the future and replacing brute force. I am still getting two cards, I have a tons of games scheduled that have support, but if NVIDIA decides to drop it completely with 4000 series then this setup will be the last of it's kind.
It will certainly take away a lot from building process. Only one GPU, maybe even some puny 16-lane platform will be enough, all games working to setup's full potential plug-and-play, that's so boring. I will need to find something to make things interesting again, like 24/7 sub ambient cooling, or making the system as small as possible.