Actually, Ann, I rather associate the gradual falling in love phenomenon with other times and places (i.e. not contemporary Western society), where love COULD develop gradually, because
• you got married by arrangement and, if the match was made well by your parents, you grew to love each other (cf. Tevye and Golde in "Fiddler")

or

•courtship was lengthy and premarital hanky panky so highly curtailed that folks actually got to know each other before acting on their infatuation/lust.

Seems to me that in our modern society gradual love is less likely to occur, because a lot of folks don't spend any time with a potential partner unless the infatuation is there to begin with. At least this appears to be the message of our mass media: if you haven't hit the sack with someone by the third date, your romance is really retarded.