http://www.ew.com/article/2015/05/15/beverly-hills-90210-turns-15

That means many of today's high schoolers weren't alive when the original 90210 was on TV.

The wheels were off the wagon (http://www.bonethefish.com/viewtopics.php?173) by then.

Jason Priestley was gone. Tiffani Thiessen had left. The show was definitely left in the dust by then.

It grew old and outdated for a show that had such a huge teen following and big impact. By the end of the '90s, it seemed stale compared with the WB Network's hip lineup (ironically, among those WB stars was Shannen Doherty)i.

The cast was top heavy (Jenny/Luke/Tori/Ian Ziering/Brian Austin were there the whole way), the cast had become a rotating bullpen of names coming and going and the chemistry wasn't the same.

It peaked in 1992-93.