I mean, the series was originally about these two out of town kids and how they dealt with life in glamorous Beverly Hills. Brenda (Shannen Doherty) was of course, already long gone and it's easy to say that losing her was already hard (https://www.reddit.com/r/BeverlyHills90210/comments/8admp6/beverly_hills_90210s_jump_the_shark_moment/) enough (https://answers.yahoo.com/question/index?qid=20080310185134AA5tZYQ). They of course and naturally, tried to fill the void that Jason Priestley left (https://www.reddit.com/r/BeverlyHills90210/comments/dzdpke/why_did_jason_priestley_leave_the_series_he_left/) by bringing back Luke Perry but by then (https://fansided.com/2020/06/27/15-shows-aired-too-long/7/), there really were no more stories to be told.