What parallel does Krakauer draw between Chris and Carl McCunn?

Carl McCunn is also often compared to McCandless. He was an amateur photographer from Texas who moved to Alaska in the 1970s, and in 1981 arranged to be flown into the wilderness for five months, where he planned to mostly shoot pictures of wildlife. He forgot, however, to arrange to be picked up, and so ended up killing himself as he slowly and painfully starved and froze to death.