Probably because what constitutes excessive is going to be a fairly arbitrary and subjective amount at any point in time and depending on the person in the case

Probably because what constitutes excessive is going to be a fairly arbitrary and subjective amount at any point in time and depending on the person in the case. I don't think that's what's really the meat of the argument. The 8th amendment not applying to states however is a huge deal as its a pretty clear violation of the 14th amendment and its broader intentions.