Like I said, a small example. But these lessons accumulate the longer you spend dating people in whom you're willing to invest love, emotion, time, and effort. Invest less, and the returns shrink. (It seems so strange to have to give the advice, "At least hook up with people you actually like!")
Thinking back on conversations about dating I've had over the years, I can think of so many lessons that friends of mine learned from early relationships: that contrary to their expectations, religion really is (or isn't) a dealbreaker for them; that a partner's clinical depression doesn't mean they're a failure for being unable to cheer him or her up; that he or she really won't change. They've drawn on some of the lessons in their serious relationships and marriages; other lessons weren't applicable. You never know which is which until you meet your significant other. And most people don't learn any of these or other lessons except through hard experience. No matter how graspable they seem in abstract, every generation relearns them.
Other lessons are delights, like learning that you're a dog person, or figuring out that your whole notion of how well you deserve to be treated was artificially low and isn't that way anymore. I'm sure years of maintaining functional, no-strings hookups offers its own lessons -- perhaps they even take less time and energy to glean (I have my doubts). I strongly suspect they're not particularly applicable to long-term relationships or marriages, if that's what you eventually want.
How much does this stuff matter? I don't know.
Often it takes getting it wrong a lot to get it right.
People used to marry much younger, and didn't have years of dating to glean lessons of the sort I'm discussing. But they lived in an era where societal expectations and marital roles were more defined. Today, young people benefit less from tradition.
Today, young people are figuring out their own sexual identity and values, what they expect out of a relationship, whether they want to marry at all, the things they want and need from their husband or wife -- "whatever works best for you and your partner" is the ethos of our era, and in many ways, that's wonderful. But finding what works for you arguably takes more self-knowledge than ever before; it is arguably harder than ever before to figure out what the person you're dating or marrying needs and wants. Often it takes getting it wrong a lot to get it right.
Plus, some of what everyone needs is a partner who understands how to balance selfishness and selflessness; how to juggle career and personal life; how to be fully invested in a relationship and also fulfill individual needs. Some people are naturally better at this than others. Perhaps women are, on average, better at this than men, and require less practice. But everyone makes and learns from mistakes. At what age is it ideal to start that effort? If your plan is to marry at 27 or 28 or 29, it seems counterintuitive to think the answer is 25 or 26 or 27, and that a shift from "no-strings" to dating to marriage is going to unfold without any major hitches.
Then again, I've never tried it, so perhaps I'm wrong.
The subhed of the New York Times article states that "for many, building a résumé, not finding a boyfriend (never mind a husband), is their main job on campus." Again, I assume there are men who would fully agree with that account of their priorities. I certainly wouldn't suggest that hunting for someone to date, or to marry, ought to be "the main job" of any college student, or a "job" at all, for that matter. But pursuing crushes and even falling in love, at least every once in a while -- rather than satisfying one's sex drive and need for intimacy via late-night-text-message-and-hookup with someone that, per the article, you don't even like talking to outside of the bedroom? I'd merely posit that, if the fun, diversion, love, and fulfillment of romance doesn't appear to be worth it based on the "life goals" cost-benefit analysis that's disconcertingly ubiquitous these days; and if one of the life goals is, in fact, marriage; then perhaps young men and women underestimate the benefits of pairing love and lust before 26, 27 or 28. I know of no tougher or more fulfilling course material; and I'm grateful that, for once, I wasn't cramming for the test.