Thats a valid point Pat, I think much of it depends on HOW those miles were accumulated, as I'm sure you understand the principle. Low rpm is the solid roller killer, inadequate
oil supply and valve adjustment as well. The same setup might give one guy 10,000 miles of "around town" low rpm duty and the next guy could get 50,000 if he's on the freeway at speed with a decent constant rpm.
MY engine, solid roller, had a bunch of miles on it before I got the car, I don't know what the previous owners driving habits were. I guess the new solid rollers address the oiling problem in a much better way now.