How long would 8 Simple Rules have lasted? I say at least six seasons, maybe up to eight seasons. Since American Idol caused it some problems midseason, 8 Simple Rules could have moved to Thursdays at 8:00 at the start of season 3 (in the John Ritter was alive scenario). NBC went rapidly down once Joey replaced Friends.

I’m sure it woulda lasted a lot longer but it depends on the writing and audience as well