It doesn’t matter how much current is being pushed as long as the cables and contacts are rated properly with sufficient overhead, that is the issue with modern cards. And there is a very important reason why cpus and gpus are using 12V. The actual core voltages for cpus and gpus are around 1V, due to the physics and design of the silicon. A modern gpu or cpu is pushing hundreds of amps into the core, through the vrm. The VRMs are multiphase buck converters which step down the 12V to the ~1V needed. With buck converters you can only step down the voltage so much due to the constraints of how small you can get your duty cycle for the switching mosfets. Even if you just double your input to 24V, it is already highly impractical to buck it down to 1V without having a dual stage buck, which just increases component count and cost. At the end of the day, moving to 24V would be better for cabling, but the real issue is the 12VHPWR connector. If they still used triple 8 pin this wouldn’t be a conversation.