I'm not sure if anything goes next to the 1DX on the right.
Look at the presentation - apart from the middle tier with 4 cameras, the 4 3 1 makes a pyramid.
If the 1DX was centered, it would ruin the entire aesthetic of the page.
The picture is meant to represent how consumers buy into the EOS system, can buy EF lenses and can upgrade their body. Thus you start with EOS-M, migrate to a real DSLR and maybe one day, to a 1-series.
For those that get into DSLRs and are serious about video, they exit stage right and move on to 1DC or C-x00.