As a child of the eighties, it feels like post PS3 things totally stagnated but this is a couple of factors working together to create the illusion that there's been no progress. First off we went from everything being 2d to everything being 3d in the course of a single console generation. There used to be huge and noticeable upgrades because models were getting so much more detail with every generation. There's also the diminishing returns they're getting on graphical enhancements; the leaps forward require massively more powerful hardware to render and most of the enhancement is in details and effects which aren't as noticeable as doubling the polygon count of your models.