It's not a chicken and egg problem, it's a balance problem. All that bandwidth, all that memory needs powerful shaders to push it as well. The point here is the shader performance of the PS4 is not high enough for 4GB+ VRAM to be a requirement. If it was don't you think Pitcairn would be using 4GB?
No. I think you missed the point, which was about
why games currently only typically need X VRAM (unmodded). With 1GB VRAM being typical, higher-res textures must be loaded and unloaded a lot, often streamed partly from the disk, or use GPU time to decompress (like Civ V).
It's not a bandwidth problem, unless you already assume that it would be impossible to make use of more VRAM at some given resolution. IE, if you assume that 1GB is enough for 1080P, then more VRAM is only needed for pushing more pixels to more buffers. I don't even play at 1080P (1680x1050), and I often get annoyed at only having 1GB, with a now-lowly GTX 460. Some games I play can use >2GB, now, and more already exist, if you're talking multiplayer; and surely more are on the way. What happens, if you run against the limit, is that it gets jerky, due to having to swap textures in and our of VRAM all the time. The answers are either pop-in/out due to streaming, or using lower-res textures. More VRAM would do the job better, without any more GPU power, or higher settings.
I'm talking about going up to something and it being fuzzy. The artist who made it likely had a much higher-res texture. But, you'll never see it. Not because you don't have enough VRAM bandwidth, but because system RAM is very far away, so the less swapping out the better, but you don't have so much VRAM to swap to and from. The bandwidth
and latency problem is on PCI-e and your CPU, not the video card; the video card end mostly has a capacity/cost problem. Even with good asset re-use, there are limits, without simply having more RAM. But, a game developer simply
cannot ignore what most people are running. Some, like Crytek, I applaud, for having options that can push the limits of what's available, today. But, I can also understand and respect the decision not to, by most devs/publishers.
IoW, the chicken and egg thing is about
why 1GB is usually enough, and it's not because the people making assets for games couldn't make them more detailed, but because without more people having more VRAM, there isn't enough incentive to make them more detailed, and possible disincentive towards trying (notice how games that push HW boundaries get called "poorly coded," and such, until the hardware catches up?); yet by game makers choosing to limit their content, there then also isn't enough incentive for users [of unmodded games] to get more, unless they need to fill more buffers faster, because the game devs have already made compromises to make <=1GB work well, even if at the cost of noticeable IQ, for objects not at a great distance.