Just to build on what Jim said regarding this stat, "the divorce rate hovering around 50%" -- this is the rate of marriages, not married people. In other words, some people get married and divorced several times, driving up this statistic, while others stay happily married for their whole lives.
After many years of mousing and thumbing, my right thumb gets sore easily and I moved my mouse to the left side. So this aspect of the iPhone is actually attractive to me. :)
"Only...audio cues"? There's a ton of research there too! (I'm prejudiced, it's what I did in grad school)... http://www.icad.org/