I agree with this gent, SLi & Crossfire are being phased out. AMD has completely removed CrossFire support from it's current 7nm product stack, the VII & Navi GPUs & Nvidia started doing the same with the Pascal range removing SLi support from the 6gb 1060 & down.
I would have agreed in 2016/2017, but things have really changed for SLi in a positive manner after 2017. I have run SLi permanently since 2004 and those two years were the worst for SLi support due to DX 12 and no one taking the multigpu lead. Some thought the API would take care of multigpu support, while card manufacturers thought game developers would pick it up, but none did - well at least nvidia did pick it up again in late 2017 and took the driver support and multigpu optimizations back in their hands. Right now I run RTX 2080 NVLink SLi and RTX 2080Ti NVLink SLi and I have only experienced great scaling and a lot of supported titles both AAA and those lesser known.