it's a bit difficult to change lenses in the middle of a match and even heavier for the back to use multiple cameras and a 200, 300 and a 400mm lens, I think the Canon sports Photographers will use 200-400/4 the same way as in international photo agencies use the Nikon 200-400 today and at sports events and that's why Canon has invested so much in their own 200-400zoom.
The lens has major benefits
The amazing thing here ankorwatt, is that I've provided very valid reasons why I can't buy this lens. Shooting at 1/500, f/4, ISO 10,000 is unacceptable to me, even with a 1Dx. Maybe you get well-lit situations, but I don't. Yes, MSU has well-lit venues, but the D2 and D3 schools I shoot for do not, and most of my football and soccer games this year will be at night.
The other thing is, I don't really miss too many shots, because I can shoot far shots with the 400 f/2.8, and have the 70-200 zoom on my other camera, and I've gotten fast enough where I can switch quickly.
But the whole topper is, this 200-400 lens didn't exist a year ago and everyone was getting along fine. Suddenly, you're arguing with me why I DO need this lens and how I cannot get shots without it, even though I've been doing so for quite awhile and others even longer than me. Not everyone shoots in ISO 100 conditions like your photos and reviewers have even admitted their concern about f/4.
I don't even know why I'm explaining this, and am wondering right now why I even do this to myself...