Can't say I agree, but that's fine. If one shoots objects in moiton, like birds or bears or planes, or models, then one likes to have fast shutter speeds. To me, that's from 1/250 to 1/500 for most of what I do. High ISO helps with that, as does fast glass. VR is wonderful, and I won't give it up where I have it, but it's not the deal breaker for me below 135mm. If one shoots still life only, or doesn't mind a puddle full of blur, then shooting at 1/5 of a second with great VR/IS assistance is wonderful.
The 100-400 is a great lens, if you can always secure great lighting. Without a lot of light, I find that 400mm at f/5.6 rather frustrating at best, or downright useless, at worst. And the image quality on that piece of glass is so terribly variable as to be as or more frustrating than the 24-105. For me, that is. If you do well with your kit, then that is wonderful. Keep it up.
In any situation where camera shake is more predominant than subject movement, the absence of VR on a lens will reduce the advantage of that great high-ISO performance of the D3s.
Whilst it's true that certain subjects such as sports events and birds in flight will require such a fast shutter speed that the prsence of VR becomes irrelevant, there are lots of relatively still subjects that do benefit from VR on a lens without a tripod. Even birds sometimes sit relatively still on their perch, just as people often sit relatively still when their portrait is taken.
In terms of both noise and resolution, I get the impression the D3s would have a 2 stop advantage over the 5D at very high ISOs. For example, I would expect the D3s at ISO 6400 to be as clean and sharp as the 5D at ISO 1600, approximately.
However, if the subject is a landscape or other subject with little or no movement, and your Nikkor lens does not have VR but your Canon lens does have IS, then in low light conditions you would likely be comparing the 5D at ISO 1600 with the D3s at ISO 12,800. I think the 5D shots would be better.
When I consider the occasions when I really wished that the high-ISO performance of my camera were better, they are sometimes situations where the use of flash and tripod are not allowed, as in most churches and museums in Italy, or in generally low light conditions where use of a flash would be intrusive.
However, there clearly are situations where that better high-ISO performance of the D3s would be of great benefit. It's just a pity that in practice I estimate I would only find such benefit useful about half the time, without a good Nikkor zoom with VR.