[hansvm]

Daniel also addressed this some, but I want to highlight that sorting one array of size 2n faster than two arrays of size n does not imply per element time decreasing to zero. E.g. if the runtime were n-2^(-n) you would have that property even though the per element runtime tends toward 1.

<rant> That kind of phenomenon (reading too far into an infinite process) is ubiquitous once you start noticing it. Infinitely many universes don't imply the existence of every possible universe (if you subscribe to such theories), pie having infinitely many digits doesn't imply that it encodes every possible message somewhere in those digits (most real numbers have that property, but iirc it's still an open question for pi), and so on. </rant>