I was away from the falconry scene for 20 years (daytime job and similar annoyances).
The last NAFA Meet I attended was in 1985. There were one or two Red Tails. The Peregrine/Prairie crosses had their own row at the weathering yard.
Next meet in 2005. The Prairie crosses were gone. Peregrines, Gyr/Peregrines, and Gyrs filled the long wing section.
The Red Tails had their own block let alone a row. I suspect a lot of the folks who had to fly a Red Tail when they were apprentices graduated to a "real falcon", got tired of driving 2 hours each way to get a slip, looked at each other and said "You remember how much fun we used to have frightening rabbits on Farmer Fred's south forty five miles out of town" and went back to the old days.

Reminiscences,
Thomas of the Long View