A lot of people, including myself, probably looked at the price and decided that they'd might as well get a 70-200mm f/4L. The flexibility and speed of having a zoom is advantageous. It's possible to zoom with the feet, but I don't want to whip out my 200mm prime, realize it's too long and have to run like mad away from my subject and still hope to catch a candid shot when I turn around. :sweatsm:
I'll be the candid one when this happens. The 200mm prime is one stop faster at the equivalent focal length, but I find the f/4 quite good in most circumstances.
On another note, I find it difficult to use even the 70-200mm lens in Singapore. Perhaps I have some difficulty 'seeing' the shot, but spaces in this country are just a tad too tight for a telephoto lens. Granted, it's nice, and useful in the right situations, but a lot of the time, 70mm on a 1.6X crop is too long for general shooting, and 200mm is too short for some events and even in the zoo.
Considering that the use of such a lens is already potentially limited, let alone a 200mm prime. However, if I did go overseas to say...Australia, I'd bet the telephoto lens will come in handy. If I got the chance to go to the 12 Apostles again, I'd probably slap on the telephoto zoom straight away. When all the other tourists are shooting the photos that've been taken too many times, I'll be zooming in for something more unusual.