eos R + 24-105R weighs the same as 6d mark II + 24-105L II. so much for the weight savings theory. like I've been saying you can justify it any way you want. it's all about the new mount and whatever camera is equipped with it. I couldn't care less if it has a mirror or not or if OVF is superior to EVF etc. it's just a camera, and i'll outsmart it .
Well there could indeed be a weight savings, but Canon err'd on the side of caution and decided they wanted a camera to mirror current DSLR sizes and then made huge lenses.
They didn't have to do that, they could have made a smaller body and smaller lenses, but that wasn't the roadmap they chose. So mirrorless does and will be lighter than DSLR equivalents, depending on who is making the gear.