because power delivery depends on a lot of other things. The most important one i could think is the cable, the ethernet cable is a dumb one, no way to tell its

because power delivery depends on a lot of other things. The most important one i could think is the cable, the ethernet cable is a dumb one, no way to tell its capability. USB-C solved this problem with the E-marker chip, which basically transform the dumb cable into smart one. Even so, the PD protocol limits how much power can be transferred.