Getting rid of these AoC rules would destroy too many lucrative markets for "illegal sexual stuff" and would defang an ancient control mechanism used by most in power. Lower AoC would impact: Lots of blackmail invalidated, CP loses value, underage prostitution would skyrocket and mafia/intelligence loses lots of leverage. Tabooing the stuff many people are biologically primed for while holding it like a carrot in front of everyone's eyes is just too good of a trauma-based control mechanism. Add in some demonization of the dirty old perpetrator cliche and you can be assured that no one would fight against this system.