You have an interesting point about consistency and I'd like to provide a counterargument. While control consistency is very important, the actual image you get from a camera varies significantly between models as the manufacturers change tone curves, colour models, etc. JPGs from the camera are basically arbitrary and RAWs are not much better. The manufacturers don't provide many guarantees, it's just up to you and downstream software to figure out what looks good. Funny that so much thought goes into designing the feel of a camera yet the photo output is basically undefined...

Also another thing, Magic Lantern adds optional features which are arbitrarily(?) not present on some models. Perhaps Canon doesn't think you're "pro enough" (e.g. spent enough money) so they don't switch on focus peeking or whatever on your model.

If you want JPGs to look different, you can change them in the camera, and RAW files are just that: raw. They will vary between cameras slightly because the cameras have different sensors. Editing RAWs from 5d3 vs. 5d4 vs. 6d (my only experience) is not very different. Ultimately, the workflow that matters is a photographer capturing the image and getting the output to the studio quickly, in high quality. Event photographers often tether via ethernet or USB and the studio can post-process the RAW in minutes (or even seconds). The part of this that is most sensitive and hardest to recover from error is the photographer capturing the image, which is why consistency and usability of camera controls is so important.

IIRC none of the EOS DSLRs had focus peaking from the factory, you need Magic Lantern -- Canon didn't program it at all.