I am not a hoof person at the least - I've always just trusted my Farrier to do his job and left it at that.
It was until one day when my Farrier couldn't put a shoe back on Nelson after he threw a shoe, due to being in Texas - I had to find another Farrier to come out and do an "emergency" shoeing for me.
This Farrier who showed up, took one look at Nelson and asked me when he was last done, I said a couple weeks ago, he said that it looked like it was a couple of months ago.
During the time my last farrier was working on Nelson - during an 8 week period, he never grew NOTHING. NOT an inch of growth. It was to the point of Nelson loosing shoes because there were no where for the nails to go.
Nails were ripping through his hooves - it was aweful. I had no clue that something was wrong. My Farrier at the time told me "he is just a TB, that is how he is. He was born with these hooves and he will die with these hooves" and I left it at that.
So - back to the Farrier who showed up......he showed me everything that was wrong with his hooves. Wrong angles, no blood flow - all causing no growth, no strength and no health.
His toes were too long, no heels what-so-ever, thin soles - all due to incorrect angles and no blood flow.
Now that I've had this new Farrier do corrective shoeing, my horses hooves are
He has growth!!! SHOCKING - he actually has growth. His heels are coming back, his toes were pulled back drastically to where they should be in accordance to his pasturns, his hips and shoulders. He actually has blood flow, and his soles are thickened up.
To boot, he moves 100x better. He keeps his shoes on too boot and they are much stronger.
SO - maybe it is your Farrier causing the problem. No blood flow causes no growth.