VRAM is a fairly easy thing to adjust for though, nearly every game I've come across that can use 6GB+ VRAM has a textures setting that has a strong correlation to VRAM usage.
Don't get me wrong, my both my current and previous cards have over 6GB VRAM and I have seen games use it, but that's because I'll have textures on ultra or whatever.
The issue is what happens over the next few years. The Ultra texture settings of now become the very high or high in 12 to 24 months time and if you are already turning down settings now on a £330 to £400 card its not going to get any better and 2 to 4 years lifespan is not unreasonable for such a card.
We will most likely have a PS5 late this year or early next year,so that will mean another push to graphics quality in games. Something like 1440p is twice the number of pixels as 1080p. Cards with RTX2060 like performance like the GTX1070/GTX1070TI/GTX1080/Vega56/Vega64 have been out for ages and all have an 8GB framebuffer. It make sense devs would target an 8GB framebuffer for the future next gen titles.
After all we are forgetting one thing here - the 60 series cards are traditional mainstream cards,aimed at mainstream resolutions,ie,1080p. Resolutions like 1440p and 4K are not considered mainstream yet(look at the stats on monitor resolutions) even though pricing has dropped a lot.People are forgetting the RTX2060 is the most expensive 60 series card in years,and Nvidia probably only considers it a true 1080p especially for its future RTX enabled games. Hence why it has a 6GB framebuffer.
Its priced at an entry level enthusiast price,but is not probably considered an enthusiast level card. The RTX2070 by its very name and the fact it has 8GB of VRAM itself is considered that card.
I'd much rather have a powerful card with the potential to bottleneck on VRAM when using inappropriate settings, than card that just simply lacks the grunt to push frames regardless of how much memory it has.
You mean like the 8800GT 256MB,which ended up failing so much within 12 to 24 months,that the slower 9600GT 512MB ended up being a better card??
People made those arguments back then,and sure it was an extreme example, but there has been a few instances even going back 16 years I can remember cards could be really limited by VRAM. For instance some of the special edition ATI 9800 series cards in prebuilt PCs which shipped with only half the VRAM of retail versions.