I don’t think that (most) Christians in my generation are making some sort of conscious choice not to marry. Many of them are making or have made practical life choices that have resulted in or contributed to prolonged singleness, but I don’t think many, if any, of them set out at age 20 to postpone marriage indefinitely. Most of them, frankly, simply lack the skills to make marriage happen. This is a big indictment on men, since they’re the initiators, but many single women also lack skill in encouraging and responding to godly masculinity when they see it. It’s also a pretty serious indictment on our parents’ generation, unfortunately. Somewhere along the line many parents forgot that they had a duty to pass on a legacy of maturity and responsibility to their children and became enablers of adultolescence instead — many parents even misguidedly encouraged their children to put off marriage as long as possible! (Side note: if you think young people today are too immature to consider marriage, the solution is not to tell them to postpone marriage; the solution is to encourage and teach them to grow up!)
But we have to begin where we are. We have to dismantle the lie that people have an expiration date past a certain age, or that a person’s singleness is either their choice or their fault — most of the time it’s really neither.