No more so than any other defined group of people. Are horse riders fickle, or football fans, pastry chefs, stone masons, doctors, airline pilots or any other group? Within the group called "photographers" are loads of very different people with very different attitudes, preferences, standards and behaviours. Some may be fickle. Others more steadfast in their choices. Personally, once I decide on something I tend to stick with it and not change my mind or be easily swayed. I tend to think that photographers are not fickle in that sense. You only have to look at the Nikon vs Canon argument to know that once we decide on something, we stand by our choices and rarely change course!!