I get your point but I actually never shoot with low shutter speeds handheld. When I want to do that kind of photography then I use a tripod. So I actually would prefer the lower weight.
But I already have the RF 24-70 L anyway now so I don't care. I know it has its flaws but all in all it's the best zoom lens I have ever owned, I'm really happy with it.
ThomasTH: Most of my tripod usage involves telephoto lenses, eclipses and the like...
...and the ability to hand-hold the RF 24-70 2.8 IS at remarkably long shutter speeds is a feature that I do not wish to relinquish.
I guess what I am admitting here is that perhaps I don't trust my own photographer's technique all that much--image stabilization is a crutch of sorts...my favorite crutch!
Seriously, though, for various travel images in locations devoid of decent light, Canon's in-lens IS has been a lifeline for me--so much so that the EF 35mm 2.0 IS lens still finds its way onto a camera of mine. I only seldom travel with a tripod.
In other words, I prefer not to rely only on the in-body stabilization that bodies such as the R5II offer.
And I agree with your assessment of the 24-70L lens--it has surpassed all of my expectations.