To be honest. Why does it even matter what other people choose as their fursona? It's their choice.
But in regards to the actual discussion I agree with a lot of the points here, There is usually a lot of characteristics about Canids that people wish they had. Sociable, Strong, quick. there is also ideals that are associated with them, like the alpha male, or the lone wolf etc. In other parts of the fandom dragons are quite popular too, mostly from the exposure and Ideals they bring, very similar to the Canid species.
Another Reason why is maybe they just choose that as a starting point and perhaps move-on to a more developed fursona later on. I know I started as a fox, then a snow leopard, then a Wolf, then a lynx, then a maine coon, then a raccoon, then a skunk, then a squirrel, then a maned wolf, and then I created my own species.
To be honest. Why should we judge on other people's fursonas at all? Just because it's popular doesn't mean it's bad. The fandom isn't a contest to see who has the most original fursona. It's a place to be the animal who you identify as being similar to, or maybe just acting like your favourite one.
I think the moral of the story is, don't judge a book by its cover. Just because they are a fox or wolf or dragon does not mean they should be thought less of. I know lots of foxes and wolves and they are all really cool furs, and all very different from one another.