Maybe it’s because “men” are always “desirable” that they seem to have a lower sense of urgency regarding time. As Cher from Clueless once elucidated (what doesn’t she elucidate, to be honest?), “Christian said he’d call the next day, but in boy time that meant Thursday.” It’s unclear whether “men” are genuinely just this blacked out about days and hours, or if they, too, feel that it’s important to play games in order to establish who will have the alleged upper hand in any emotional dealings.
Even when a “man” at first seems suspiciously into it (it’s always suspicious, as affections never endure to the same level of intensity as the outset), and you think he might actually text you to make arrangements in a timely fashion, his interest will fall by the wayside after a day, and you probably won’t hear from him for another three. You see, they have “options,” other butterflies to get distracted by like the little skunk from Bambi that they are. And whenever they feel that they’ve totally exhausted all of their distractions, then, maybe, they’ll resort to getting back to you.
In the end, they’re the ones with time on their side (which is why the all-male Rolling Stones sing a song called “Time Is On Your Side”–and it really has been for Mick and Keith). They have nothing to worry about when it comes to being viewed as a shriveled carcass once they exit their twenties, so this is probably where the laxity stems from with regard to keeping the momentum of attraction going.