Not so fast — what’s so “premature” about premature ejaculation?

The function of ejaculation isn't really a mysterious biological occurrence…it's an evolved mechanism designed by nature to launch semen, and therefore sperm cells, as far into the dark, labyrinthine abyss of the female reproductive tract as possible. And once one of these skyrocketed male gametes, in a vigorous race against millions of other single-tasked cells, finds and penetrates a fertile ovum, and—miracle of miracles—successful conception occurs, well then natural selection can congratulate itself on a job well done.

So given these basic biological facts, and assuming that ejaculation is not so premature that it occurs prior to intromission and sperm cells find themselves awkwardly outside of a woman's reproductive tract flopping about like fish out of water, what, exactly, is so "premature" about premature ejaculation? In fact, all else being equal, in the ancestral past, wouldn't there likely have been some reproductive advantages to ejaculating as quickly as possible during intravaginal intercourse—such as, oh, I don't know, inseminating as many females as possible in as short a time frame as possible? or allowing our ancestors to focus on other adaptive behaviors aside from sex? or perhaps, under surreptitious mating conditions, doing the deed quickly and expeditiously without causing a big scene?