Hawkeye, you didn't understood me. I didn't said that the less talented players choose clay. I said that they had success on this surfaces because the best had ill suited games for clay. They were competing between themselves, with the occasional presence of an attacking player in the later rounds of the tournaments.
The weakness of these players is shown by their vulnerability to the attacking players and also to their vulnerability to nobodies like Meligeri, Dewulf, Svensson, etc. (see my previous post for the full list). These one semi-final wonder did not exist on the same extent in other surfaces. A point you did not address in your answer.
The players who "dominated" clay didn't not choose clay because they were less talented, they had success on clay because it was the surfaces were room was available for them. Just like clay was the surface which was available for Rosset and Dewulf to reach a slam semi-final.
The effective split of the field by surfaces allowed player to become surfaces specialist. But being a specialist doesn't mean that they were better player on the surfaces than generalist from a decade later.