I actually first noticed it with Gen 6 consoles. They were huge upgrades from PS1 and N64, but they didn't look "just like a movie" which was the unrealistic expectations we had of the primitive 3D graphics at the time. Since then, each progressive generation has had noticeable but smaller returns. PS3/360 games were another (slightly) smaller leap up from Gamecube and OG Xbox, which improved over the course of the generation, and Gen 8 has seen its leap diminish as well.
Don't get me wrong, games from the middle of one Gen to another are still obvious upgrades. We are nowhere close to the limits of how good games can look, but we are reaching a time where improvements in visuals are mostly in the fine details now - and not as over-the-top impressive as, say, the leaps from 2600 to NES to SNES to N64. We saw so much happen in that time frame that everything that's happened since 2000 seems to be at a much slower pace.
Retro Tech Select - My Youtube channel. Covers throwback consumer electronics with a focus on "vid'ya games."
Latest Video: Top 12: Best Games on the N64 - Special Features, Episode 7
