Using a higher voltage is not an innovation (it's an obvious change, and we've gone from 6V to 12V to, in some cases, 24V already) - rather it's just a slight efficiency improvement in largely non-critical systems, with not a lot of incentive to take on the cost of transition.
In a a personal ICE vehicle, the only real significant power was to the starter motor and from the generator, and the distance there was short so the copper didn't really matter and thus no one cared for 24V - unlike industry where you might have significant aux systems. With EVs, you have heat pumps and brake boosters on the auxillary power, so you now have a stronger driver for conversion.
Even within 12V, you'd get a larger weight reduction from not carrying an aux battery, and just feeding through a converter from the HV system.