Eh both of those statistics are wrong. We'll never know how many people did this. WoD has literally nothing to do so maybe that's what a lot of people focused on, or they just left without doing it. I only have 1 level 100 with a serious maxed out gold grabbing garrison, and another with just a level 3 garrison.
I can't see many people doing the "50k a day" thing though, that's a lot of level 100s with maxed out garrisons, not even going to get into the "100k a day" thing. I wouldn't be able to even look at wow if I did that, it would push me far beyond the boundary of burnt out.