Even worse argument there, I can play with 4GB VRAM all the same, just lower the details setting to Medium and voila. Not sure if you have tried but RT reflections and Transparent Reflection is much more noticeable in game than Ultra details vs Medium. Furthermore all RTX games will come with DLSS, so yeah, not sure what manual you read regarding VRAM for future proofing.
Well if you state it that way then there is no need for future proofing, every GPU is obsolete when its successor come out anyway. So why bother with 8GB or 10GB VRAM, can't play game with anything less than Ultra High settings ?
I would pretty much prefer RT to Ultra High settings, at least it doesn't need 400% magnification to distinguish.