nVidia only supporting 1.4 is ... crap.
Their rationale was that 1.4 can already support 8k at 60Hz ... which is true.
But it needs lossy compression (DSC) or lower color depth to support 4K HDR beyond 120Hz. And we do have displays today that can exceed this being sold very commonly.
You can argue that the color depth only matters to pros, or that HDR is a mess on PC and doesn't matter anyway, or that DSC is virtually indistinguishable from the source video... but DP 2.0 eliminates all of those arguments entirely, is a published standard today, and is ~3x the bandwidth of 1.4 - you can drive 2 displays at 4k > 120Hz HDR without compression at all.
I suppose you can also argue that today's cards aren't fast enough to drive two 4k displays at high refresh rates - maybe that's true... not a great thing for nVidia to admit with it's brand new Ada chipset and DLSS 3 though, if you wanted to hang your hat on that particular rationale.
Reality - either it was just an oversite... possible. Or they couldn't make it work... I kinda doubt this one. Or nVidia just doesn't want to eat into their margin to provide it to you, because "you can already use 8k 60Hz". I would say they don't want to overprice their cards, but ... who could possibly say that with a straight face today?