I don't actually agree with your statement that if they were any good the pro's would move to them.
They are sponsored, they play the clubs the sponsors provide and their set of clubs can run over $3000 without even thinking about it.
They have their clubs tweaked every week/month depending on how they 'think' they are playing. Golf is a mind game as much as anything.
Not trying to be offensive here at all. Everyone has a different approach and what works for one guy or gal is good enough, we should leave it at that.
I have hybrids, lots of people think these are not 'real golf clubs'. I should be hitting forged they say or Pings or whatever.
Well I hit my 7 through 3 hybrid quite well and use standard cavity back short irons. None of them have failed me.
By the way, all of my hybrids are the same length (well nearly). 7 through 5 the same length, 3 and 4 the same length. (only one half inch difference in the two groups)
Now I'm not like a bunch of guys and gals out here knocking the ball off the tee 300 plus yards as I see regularly stated. I never will. Too old and broken.
But I can stay in the fairway from tee to green all the time. It's just up to my swing being correct, steady and consistent. This is where I think the same length clubs have helped me.
Not for everyone, but if it helps one person, then that one person should go with it. Golfs a game, supposed to be enjoyed not frustrating and none of us that I know makes his or her living playing golf exclusively.