this chart is for natural people, so we take steroids to have increased protein synthesis 24/7
I agree that steroids obviously increase recovery time, so therefore you wouldn't be limited to the 6-8 sets before diminishing returns set in. But most likely it would still be more beneficial to break this up into more frequency (2x per week instead of 1x for example). And some people may have superior genetics that have much better recovery as well.
So, you most definitely can still get freakishly huge doing a 1x per week split if you fall into one of these categories. But not because it's the most optimum way to train.