Not a lot have change, but if you're watching movies filmed in the 60's, 70's, 80's, 90's, this is 2017. . . YOU'LL know why those are not worn today! Outdated, is when you see jeans from those era, not popular, you wouldn't find them in modern stores, except Goodwill, or eBay?
the 60's, looser, they come down to the ankle, your socks showed.
the 70's, bell bottom, tight around the butt. Polyester, they just came out.
the 80's, ripped jeans.
the 90's, Rob Lowe's movies, baggy jeans.
2017: skinny legs with stretch. Levi's didn't have stretch in the earlier jeans, but 501 is popular (buttoned down front).
Many styles are classic, meaning VINTAGE IS ALWAYS IN, and classic styles NEVER go out of style.
Other times, they just come & go, and come back again.