That chart also needs to show that 100% of worst photographs also belong to the iPhone and NOT from Canon or Nikon.
Now that's just silly, and I assume you know it's not true and are just trolling.
Even so (or if you were being serious), it seems like there's something about owning a larger camera that causes some people to develop this weird mental state in which a bigger lens, shallower depth of field, larger sensor, or more expensive camera automatically equates to "better" photos. Which is transparently ridiculous. You can take a terrible photo with a D4S or a 1DX or a medium-format Hasselblad and a $5000 lens, and you can take a gorgeous photo with an iPhone. Heck, there's a reason pro photographers have for all of recent history taken vast numbers of photos--a lot of them don't come out well at all.
And I say this as someone who owns a pretty decent system camera, a half dozen lenses, and just this week spent well over $1000 on a single lens for it. I own this stuff because there are some shots that, for reasons of focal length or aperture or light gathering capability I can't take with an iPhone, other shots are more "fun" to shoot with a larger camera, and I like to play with RAWs. But I also know perfectly well that there are plenty of beautiful photos to be taken with an iPhone, and I've taken a few nice ones myself.
I'm also sure that a talented photographer armed with nothing but an iPhone, given appropriate subject matter, could take much more attractive photos than I can take, no matter how expensive of a camera you give me.
It's fine to own a big, expensive camera and love it. I do. It's fine to own an iPhone and be happy with it as all the camera you personally need to take the photos you want to take. What I have trouble understanding is why some people get so worked up over the idea that someone, somewhere, might be taking a really nice photo with a smaller sensor than they have. I can only assume it has something to do with jealousy--the fear that expensive hardware just isn't enough to compensate for the person's own lack of talent. There are of course those who feel the same way about belittling anyone who owns a large camera or fancy lens, but pixel-fanatic big-camera fans seem to be much worse on average, at least in comment sections.