Flyfishing is a very effective means of fishing that can outperform gear under certain conditions.
1) The fly angler has to be able to cast, if you can't cast, you will not be in the game at all.
2) The fly angler knows what technique and fly will work when and where. In other words the successful fly angler has to improve his knowledge and skill set to a much higher degree in order to be consistently successful. Without this knowledge you will reaching for the worm bucket more often than your fly box to catch a fish.
3) Flyfishing requires fairly clear water as we rely on primarily visual triggers to get the fish to eat our flies.
4) Flyfishing does have an advantage for fishing shallow water (say less than 3 feet deep) or near the surface to fish that feed by sight and spook easily. Call it the stealth factor - the abilty to cast extremely light weight lures (flies) that land softly and do not sink quickly.
5) A good flyangler will not be handicapped in water depths of 3 - 10 feet if he has the knowledge, skill and fly tackle to fish these depths with fly gear but he doesn't have the advantage anymore over other tackle.
5) Fly anglers can still catch fish at depths over 10 feet, but gear has a decided advantage in deeper water.
6) Finally some species and / or circumstances were simply made for flyfishing, ie mountain stream cutthroats or post spawn pike and walleye in shallow water. Here in Alberta I can catch 6-12 pike / walleye per hour pretty much through the whole month of June. By comparison my gear fishing friends will catch 2 - 6 fish per hour. However come July I am hard pressed to get any walleye on the fly once they drop down deeper and require an additional trigger (such as a minnow to appeal to their sense of smell and taste) to get them to eat.
I have been flyfishing for 40 years now. Eventually you become rather shallow minded and seek out those species and situations that favour the fly rod, so under those circumstances you should outfish the gear guys. For me that means post spawn pike in the spring, mountain trout in the summer and Carribean bonefish in the winter!!!
Tight Lines!
Guy