The first through third generations aged pretty poorly for the most part. The fourth gen systems have aged the best of any generation. The fifth gen systems aged better than the third, but nowhere near as well as the fourth. The sixth generation aged better than the fifth but still not as well as the fourth. The seventh gen is interesting, because there's a big difference in how well early games like Oblivion, the first Mass Effect, Assassin's Creed, Resistance, ect. have aged compared to later games from that generation. I don't think any generation has had such a big difference between early and late gen titles. Though the current gen may have a bigger difference, as the libraries of the PS4 and XBOX1 sucked for a long while after launch. It was only really in 2015 that the current gen started to come together.