The pick of the litter. Well Gable appeared to get that, no doubt, and as we all know recruiting services weren't the same as they are now.
The thing is, Gable ALSO took kids(mostly from the state of Iowa), that weren the "pick of the litter" as you say and turned them into all Americans. Did he win all those titles off just that kind of kid? Well, no, he didn't, but it is one of the things that made both he and his program legendary.
One example that comes to mind is Travis Fiser. If memory serves, he was a state runner up at Iowa Valley Marengo, and ended up being a 2-time all-American Under Gable. Clearly a tribute so to speak to Gable and his coaching ability, and of course the guts and determination of Fiser himself, a kid that wasn't a big recruit at all. There are of course more stories like this.
It's not "myth-making" as you so eloquently stated. He did do it, with out a doubt. As I said before, did he win all those titles and set records with just those kids? Well of course not, but this is a big difference between what he did and what Cael is now doing. Cael hasn't had "that story" yet. Now in fairness to Cael, maybe he hasn't had to, as the bulk of he is recruits and subsequent starters are top ten P4P kids with major national and international accolades behind there names.