The question is this: if it's not about the gear, why does the pro use the best stuff? Surely, the reasoning would go, if you can take all great shots all of the time, with anything, the pro will buy cheap, because that keeps their costs down.
For me, this is a hobby. I buy the best I can afford because I want it. I'm a gear-head, so what? But if I were a pro, I'd be a businessman, and I'd need my costs down, because if my costs are down, my profits are up for the same given revenue.
Pros are not buying the best gear because they have an emotional attachment to Canon. And since getting better gear, my keeper rate has gone up by around 20%. Perhaps it's all in my mind?