The below quote is from his article found here: http://kenrockwell.com/leica/cartier-bresson.htm and I think that he is probably right on the money. 😀
" [FONT=Helvetica, Arial, sans-serif]Then the light turned on. After many decades of thinking Cartier-Bresson shot with just one lens because it let him shoot faster and smoother, I realized that Cartier-Bresson was, duh, a journalist. Journalists don't get paid anything. They aren't the rich hobbyists who buy Leicas, romanticize about the fascination and unique "Leica look," which is how the cameras look sitting in their glass display cases and Danish Royal Wedding presentation boxes.[/FONT]
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Cartier-Bresson obviously went to a Parisian camera store, and bought his Leica and lens after much saving and scrimping. [/FONT]
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He liked it, and when he went back to get another lens, found out the price, shouted "Merde!" and promptly waked out. Cartier-Bresson never again dared to return to a camera store.[/FONT]
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That's why he only shot with one lens his whole career: it's all he could afford!"[/FONT]
EDIT: the smiley face means that I do not believe what KR is saying here, but understand that he writes in jest. The whole article is a sarcastic editorial on the price of the Nikon Dx3 and should be read as such.