Skyrim may have come out 14 years ago, but it's been rereleased literally a dozen times. It can't be an "old, classic" if it's literally never left the pop culture zeitgeist because it comes out every year.
I think that as the longer videos have existed, the broader the category known as "modern video games" should be chronologically.
We're also at the point where we're just not seeing any significant upgrades in graphics anymore. The cutting-edge graphics from ten years ago look more or less the same as those from today. When you combine that with non-AAA studios developing modern games with less advanced graphics, it gets harder and harder to date games based on looks alone.
