Why did king of queens go off air?

It was on for about 9 years and although we all love shows like King of Queens, it life span seems to be between 7 and 10 years. Lately, I have watched King of Queens, Yes, Dear, Everybody Loves Raymond and of course Seinfeld and it's hard to believe that all that I watch are these shows either re-run on FOX or TBS and then I tune to Nick at Nite or TV Land to watch even older re-runs. This speaks volumns on people and their watching habits and then for tv exec's why don't they see we don't care for what on in the new "category". TGFR...thank God for re-runs.