Retiredweaxman, There are some more costs that you haven't thought of for a photographer covering an event. There are a few different ways photogs do events. Some shoot an event for a paper, and then try to privately sell. This can make some extra bucks here and there. Other photographers get a contract with the event or school and become the official photog for that event. This will cost the photog either straight out of his pocket or a percent of his sales. The third way is to be hired by parents of the kids to shoot their child at the event. This is usually for a fee and they pay for prints after.
The other items that you have to factor in, equipment, travel expense to and from the event, photogs time shooting that event, cost of software, and insurance on you gear. For example if a photog travels to say high school "X" fifteen miles away. That is 30 miles round trip, and about 40 minutes of driving time to cover a 2-3 hour event. Now we are at close to 3-4 hours if you include processing the photo. Equipment can run a photographer a lot of money. From mid level to upper level DSLR with lenses your are looking at $10,000 to $30,000 that a photog can carry to an event. Then also figure in the cost of a program like Photoshop or Lightroom. Granted you have to spread all these cost out over a lot of sells, but you can see how it brings the cost of a photo up.
This debate has been going for years and is nothing new. Pros miss out on possible sells do to parents with a camera, taking photos at the same event. In most cases people aren't interested in quality of the photos, just that they get one of their child playing a sport. The best way for a pro to make it in event photography is to contract with the school to be the official photog. This usually means the pro would have sideline access and others would not be able to shoot from the same areas. I have shot events like this before, even swim meets. Parents had to stay back from the pool a certain distance, while myself and the photographer I was working for could get right up to the edge of the pool. The biggest thing though, is your photos have to stand out over what others are shooting, in quality and in capturing the right moments.
Do I wish people would not give their photos away, yes I do. Is there anything I can do about it, nope! So I move on, take the best photos I can, and try to stand out over and above the others taking photos at the event.
I am not a pro, I don't make 51% of my living taking photos, but I have worked news media, events, and private sells of photography, so classify me as you will.