It's really easy to cherry pick out the examples you want. Here, I'll try. How did Kerry Wood and Mark Prior's careers turn out? See how easy that is? You also can't really look at someone's career and say with any certainty "the inning limits and the proper usage of him have maximized his potential" because you can't directly compare the alternative.
It's easy for a fan to say "well Kershaw went on the IL anyway so obviously that strategy didn't work", but you and I have no idea what impacts that game had on him or would have had on him had he continued pitching. He went on the IL with pelvis/back injury 4 starts after that perfect game try....should we link that to the decision of his first start?
There are experts who study this for a living. I'm inclined to trust the decisions from the organizations that are spending millions on athletes, trying to win a championship. Even if it wouldn't have had any impact on Kershaw's health this season, there was risk that it would have. As the Dodgers, that risk isn't worth personal glory IMO.