When I was young and starting as a commercial photographer I had Leica range finder. The studio had Nikon 35mm SLR, Hasselblad SLR, Rollie TLR, and view cameras (4x5, 5x7, 8x10). Each had a different "view finder". Each was used for its benefits and managed for its weaknesses. With a few exceptions the same film emulsions could be used in any of the cameras. Often, we would shoot the same subject with multiple cameras to give the customer different sized transparencies and/or negatives.
Now I have digital cameras. For years I used Canon, simply because I had Canon lenses and it was easier to buy the next body than it was to buy new lenses.
Over a period of about 18 months I transitioned from buying a Fuji XPro 1 for personal use. (Poor man's digital range finder) to a full kit of Fuji XT-1s and lenses. The motivation had nothing to do with view finders, it had to do with liking the smaller sized kit and realizing I was getting good images.
I got a Sony A7R to shoot architecture with my Canon TSE lenses. That led to getting a couple of lenses so I could carry one camera on projects rather than two. Over another 6 months I've now found that I like the Sony kit for general work because it simplifies my life. i.e. not needing two kits.
Does this all mean I think Sony is better than Canon or Fuji? No. It does fit my needs better than either. It has its limitations. But then again, I always had things I wished the Canon kit or Fuji kit could do better too.
In my view, the great benefit of digital is its ability to reduce the complexity of hardware, and make processing images so much easier and better in software than it was in a darkroom and retouchers studio.
As for 800 lb. gorillas, the history of business is littered with their graves. Northern Telecom, Lucent Technologies, Fore Systems, MCI/Worldcom, the Bell System, IBM PCs, Sun Microsystems, [Pick a steel company]. And the list could go on for pages.
My point is, we have to pick the tools that work for us. And, we have to respect that others may pick different tools. Vivian Meier used a TTL, Henri Cartier-Bresson used a Leica, the Navy photographer who shot the flag raising at Iwo Jima used a Speed Graphic. There are great photographs being made today with every kind of digital camera, including iPhones.
To paraphrase one of Bill Clinton's political advisors; "Its the PICTURE stupid!"
And now on to something productive.