1. I accept your point that those with limited capital sometimes need to sacrifice their potential -- if you can't afford college then your annual income will be lower (though perhaps not lifetime income).

2. Diminishing marginal utility is not usually considered to apply to time -- are you saying that your girlfriend would rather use a mac than add an additional ~year of work/play time to her lifespan?

3. Note that the concept of diminishing marginal utility is different than the concept of utility.

4. I'm like this in person.