Unless Nvidia are keeping something a big secret, like some card sitting between the 3080 and 3090. then I think that it may indeed be possible that they are trying to make the 3090 look as appealing as possible to milk initial sales.
Having a 10GB 3080 seems cynical even by Nvidia "baseline spec" standards and MS Flightsim 2020 has already been shows to take more than 12GB VRAM at 4k (
https://www.guru3d.com/articles-pag...-graphics-performance-benchmark-review,4.html), so if true this is a poor and short-sighted move by Nvidia, as even if they have the most amazing memory compression and efficiency technology, people will still be put off by it.
I have a feeling, like others have said above, that AIB's will be the ones adding more VRAM configs and charging a handsome price for it.