Efficiency as far as size and numbers of fish brought to hand is not where the payoff of flyfishing lies.
If you are looking for "efficiency" then live bait and 20# line would be the way to go.
Just as rifle hunters turn to bowhunting and compound bowhunters turn to recurve/longbows....Sportsmen eventually, after a certain amount of success will look for ways increasingly more gratifying to feed their egos.
In this day and age we aren't fishing to stockpile food, and most of us aren't even trying to fill a bag with 5 of the heaviest fish in the lake. I went back to flyfishing after I realized that cranking down on multiple 4-7lbers with heavy tackle and swinging them over the gunnels like a 9" crappie didn't excite me anymore, and also realizing that after a day of doing well I really didn't feel a sense of accomplishment.
Even if I placed well in a tournament and took some money home it was still less than I could have made by rebuilding someones outboard. I'd much rather take your money by working on your boat/motor than to TRY to beat you at fishing on any random day. I'm way more confident in my engine repairing skills than I am my fishing prowess.
I get remembered everytime someone turns a key to start their motor. They either think kindly of me when it fires right up....or cuss me when it doesn't. But the guys whose money I've taken by getting bigger bites than they did once upon a time....they probably forgot my name before they even got home.
So flyfishing is about Me feeling good about what I'm doing. The construction of the flies and leaders, the placement of the cast, the manipulation of the flies, ect. It is just so much more involved and harder to do, so when I succeed it makes me happier than catching the same (or more) fish using conventional gear.
You can't deny the elitist aspect of flyfishing because it truly is a graduation of technique and mindset that is advanced compared to other forms of sportfishing. What other form of fishing requires as much preparation, practice, skill,
stamina, and problem solving in order to be successful, regardless of the species you are targeting?
It's all about the personal payoff. But even at that it isn't enough for me to just be "fishing with a flyrod" since drifting midges under a indicator with a flyrod takes less skill than huckin' a roostertail all day. Some forms of "flyfishing" can be pretty lame in the payoff category.