Most people seem to begin with canine fusonas [or sometimes with feline] and as time goes by and they are getting more experience, and maybe more aware of their inner furry self they change it to something that fits them the best. I've meet bout wolfes, whose personality went great with that fur, and the rarest-animal-avalible fursonas, that, well, were dull, and it could be clearly seen that they chosen one to be 'original'.
Why so many foxes/canines? The fandom grows every day, and like I said, people tend to begin with those animals, maybe because they either know them best, or they are commonly liked/adored.
I began with being 'another' canine/wolf, then equine, zebra, and finally my fluffy long-tailed self ^^