Should Photographers Specialize?

Professional photographers often advise us to specialize in one type of photography. The logic they use revolves around mastery; if you don’t specialize, you won’t master any type of image-making, and therefore won’t ever become the best, or one of the best, in that field. I would beg to differ. Generalization will do more for our photography than specialization.
If we generalize, we learn skills in one type of photography that transfer to another. For example, I did mostly natural light photography for many years, never really mastering flash photography. My occasional portrait sessions suffered for my lack of flash skill. Then, when out in a small Colorado town capturing a large, one-room museum with a group of photographer friends, I mentioned my difficulty in filling the room with my flash to a wiser photographer. Voila, in a few minutes, my friend taught me the correct settings to get really good flash results. In the couple years since then, I’ve used those settings successfully for portraits and weddings.
Another case in transferable skills came through non-photographer friends. A married couple who I’ve known for many years (several decades, actually) belong to the local Porsche club. They participate in the club’s track days several times a year at a private course in out in the rural plains east of Denver. More experienced club members teach less experienced members racing skills. My friends have invited me out to the track days to photograph the cars in motion. From these sessions, I’ve improved my panning skills, enabling me get the cars in sharp focus while blurring the background. Since the more experienced drivers often exceed 100 MPH, I’ve learned to anticipate the motion of the cars, and follow them with my lens before snapping any shots. Learning this skill in a controlled, yet challenging, environment provides me with the skills to do sports and wildlife photography better. What better way to capture a sprinter in a race, or an eagle in flight, than to know how to pan while anticipating the motion of the subject?
I also enjoy taking photos of vintage cars, such as a ’67 Mustang that a friend was customizing. We picked the exterior of an abandoned factory as a backdrop. At the time of the photo session, the car was in a transitional state, with some of the custom body work done, and a lot of primered sections, and some bare metal. The rough exterior of the factory worked well with the rough state of the car. The skills I used to capture the car corresponded to the skills I use for flower photography. How? First, I needed to understand the angles at which the subject looked its best. Second, I needed to understand the importance of the background to the success of the image. Third, I used HDR for the car images, which I often use for flowers; HDR photography with flowers is actually more challenging than cars, since the slightest breeze will move a flower significantly, and requires a great deal of patience to wait for that perfectly still moment or two when several exposures can be made. By comparison, car photography is simple, and I can do it quickly and easily because I’ve learned the technique on a harder subject.
So, generalizing in photography will make us better photographers when  we happen on a specialized situation that we’ve never encountered before.