I haven't read the book - heard an interview with the author.
I like the principles of Maken's book (gift of celibacy applied too broadly today, e.g.). Some singles may need a fire under them to learn and take the steps they can toward marriage. But these things can come across too rigidly. At least in the interview I heard, there was an undue pressure on singles and sometimes outright maligning of them ("what's wrong with you that you aren't married yet?").
The biggest problem is for singles who want to be married but find it just not happening yet logistically, or no opportunities, etc. Young men do need to learn to "take a wife," but this doesn't mean it is like getting bread from the grocery store. What if no one wants to marry them? Fathers of potential mates find their maturity adequate but not up to their standards, they have personality quirks that obscure their maturity, etc. Singles aren't the only ones responsible to see themselves married. This takes a concerted effort by the family of God.