Being able to divide people into independent-minded and conventionally-minded is itself conventional thinking. It's also sadly narrow. There is no one I know who is independently minded in all disciplines of life or, likewise, conventionally minded. In sports, there's no one as independently-minded as the top stars (read reviews by their coaches and teammates for a sense of this). But in other disciplines, especially religion, they're are amost the most conventionally minded: adopting all sorts of rituals to solicit the help of God during the game.

This extends beyond sports. Descartes, arguably the father of modern philosophy, was a devout Catholic, even refusing to publish a paper after Galileo's declaration got him in trouble with the Catholic Church. If the soubriquet "father of modern philosophy" doesn't imply independent thinking, I don't know what else would. And then there's his Meditations on First Philosophy where he's severely blinded by conventional-mindedness to "discover" God as the first principle.

I guess what I'm trying to say is that, someone writing about independent- and conventional-mindedness should at least take some pain to explain that in any individual you'll see both. That there are no independent-minded people nor conventional-minded people, but only in ways that we carry out our activities.