Maybe I did not articulate it properly, but this was my point. Even if 100% of Mac owners had iphones, there are still 93% of computer owners have a non Mac PC. So that 93% is a huge amount of people. Since there are way way way more iphones out there than Macs, logically, there has to be way way more non Mac using iphone customers than Mac using ones. Even if you accounted for the (very few) non windows computer users, there would still be a much larger proportion of people using a windows pc and an iphone, than the amount of people using a Mac pc and an iphone.
To break it down further. Let's say there are 1000 iphones out there. And lets say each of those iphone customers has a computer. So 7% of 1000 iphones is 70 Macs. That leaves 930 Windows computers (or the negligible amount of other computer types included). So if every single Mac user uses an iphone, it's still only 7% or 70 iphones.
So there are still 930 iphones out there. So even if only half of them had computers (or access to one) if would be 465 windows pc using iphone customers. Now if even half of them used iphones (as compared to other phones), we are still looking at 235.5 people that are windows pc users using iphones. or 3.5 times as many windows pc users with an iphone, as compared to mac users with an iphone.
Obviously the numbers are not scientific based, but I think you get the picture. On a side note, I only know 1 person with an iphone and a mac, but everyone that i know with an iphone (i only know 2 people with non iphone smartphones) they either all have a windows pc, or don't have a computer. Mostly because windows pc are simply cheaper, more options, and people are more used to them as they are more prolific in stores.