There are Fly tyers who excel at tying but scarcely catch any fish
there are those who "Fluff Chuck" (a Northern Anglers nick-name for someone who fly fishes) who can catch any species but don't have the first idea of HOW to tye a fly (Notice I use the OLDE English word for tying).
I personally would not class the tying of a fly as a sport but as an ART or art-form as there are many different materials that an expert tyer will join together to form a representation of an insect or fish.
The sport of selecting the correct type of fly or bug to the prevailing weather insect hatch or water colour is something that take many years to perfect
To stand at the waters edge and persuade a wild trout that your fly /pupae/lure is edible and to try and eat it is something else. It's you versus nature and with so many variables it can boggle the mind of someone who doesn't participate, some days you can change just the colour of a fly somedays as many variables as you want without success, that's the sport.