I agree with Bob that a lot of these discussions are rationalisations - "I spent all this money because it's the Best Tool for The Job (even though photography isn't my job)" ... "Buying expensive cameras is a waste of time because it's All About The Picture (but give me half a chance and I'd buy one like a shot)"
I also think this idea of the camera as a "tool" leads up the garden path ... it tends to support the idea that the "best" camera is one with "high performance" .. all measurable of course with ratings and pixel counts and noise thresholds and all that bollocks.
Whereas the truth of the matter is that people give as much weight in their choices to brand cachet, looks, feel and general desirability as to anything supposedly "objective". People buy a camera because they want that camera, not this camera, and much of the rationalisation that Bob refers to is about fooling oneself that one is making objective choices rather than subjective ones.
Now, to be frank, it really doesn't matter - in a consumer society where the people concerned have income to spare, and nobody goes without food or shelter because they buy a camera - whether you choose a camera just because you want one; but lets just not pretend otherwise ...
When I was a roofer (this is the early '80s), I spent half a week's wages on a hammer; Now I could have banged nails in with a rock, or a Nikon F probably, but I didn't.
Instead I chose to use a 16oz Estwing single-forged hammer with solid nylon grip.
Why? Because it was a very cool thing for a jobbing roofer to own, and I thought it looked cool, and I could. Still got one, actually. I can never find it though, and if I need a hammer I sometimes use a spoon or a book.
Is it time for my medication now, Nurse?