I don't really see it as an additive to friendship. The way I see it, when you are interested in a woman, you go through a few stages directed towards marriage: seeing if it's worthwhile to get to know each other more intimately with a view towards discerning whether you ought to marry each other, getting to know each other more intimately with a view towards discerning whether you ought to marry each other, discerning whether to marry each other, and then marriage. When I suggest that he ask her out, I am suggesting that he do step 1 and signal his intention to begin this process. I suppose you can do part of step 1 without telling her you're interested, and you probably should do some of the groundwork of step 1 before telling her you're interested, since, well, the alternative is asking her out the moment you meet her (which isn't a terrible idea, but it's not a wildly successful one). Anyway, I married my wife a little over a year after meeting her, so, make of my advice what you will.
And your argument is a little absurd. Traditionally, people didn't date. The stuff you see in Jane Austen novels was commonplace among the upper classes. The lower classes usually had even less dithering about and marriages were frequently arranged. It was terribly common for people of some short acquaintance to become engaged, and quite often the first open expression of romantic interest was a marriage proposal. "Dating", where people express romantic interest in each other, "go steady", eventually get engaged, and get married is a thoroughly modern activity, modern enough that I think it's silly to refer to its "origins". And note that even in its origins people got engaged rather quickly by our post-modern standards. Which doesn't really have any bearing on anything you're saying, but it bears mentioning.
Anyway, the template I mentioned above should take between 1 and 2 years. With me and my wife, it was a little over a year from when I met her that we got married.