If Canon were to dramatically lose market share, it won't be because of all the reasons stated on this forum. It will be because all of the bad publicity generated by internet forums and review sites. People searching for a new camera will be using the internet - and as we have seen in other cases - internet information can have a huge negative impact.
The problem for Canon is not that their products aren't competitive, but that they are being judged on the internet by folks who are all "technology" biased. When comparing spec sheets and technological add-ons (focus peaking, zebras, etc.) Canon has definitely been behind Sony. The negative "talk" is quite overwhelming - and in almost all cases - biased and prejudiced beyond reality. In an effort to create a more honest perspective, a few folks spend way too much time on this and other forums just trying to combat the negative propaganda. Quite frankly, I am ready to quit. I'm sure many of you will be quite glad to see me go.
If folks mainly interested in photography - not technology were running the forums and review sites, I am sure Canon would be seen in a much different light. Many would say they are still ahead in color science. Many would say that they are the leaders in reliability. Many would say - for almost all photographers and not pixel peepers - the IQ of all similar level cameras is essentially equal. Many would say that their lens quality and selection is second to none. But to the technologically biased, it is all about pixel peeping, testing underexposure of 5 stops, and how many "cool" things you can add to the camera to make it "innovative."
I have owned Canon, Olympus and Sony cameras. I am in the process of trying out an Olympus E-M1 mark II. It's a pro level camera costing twice the Canon M5. And I really like the Olympus system, but guess what, their new Touch AF while looking through the EVF doesn't work very well while Canon's works great. For regular HD video that the average consumer will use for home videos and the like, Canon's DPAF still makes video AF better. Overall, the best pics, in my opinion, still come from Canon when you factor in color and contrast and their tonal curves.
So, the danger for Canon isn't in the quality of their products. It is in the bias and prejudice of the internet review sites and forums, in my opinion. If you know anyone looking to buy a new camera, tell them to try them out themselves and form their own opinion - and stay away from the internet! 8)