There are certainly a few contexts I can think of where some people, for particular reasons, might better “do their part” for the world by not getting married and having children...but I feel pretty confident in saying that most modern people who aren’t having kids on purpose don’t fall within that pretty narrow subset. Refusing family life so you can have more money to blow on self-indulgence and “living your best life” is not flourishing as a person. It reflects a disposition of selfishness, not of love and sacrifice, and it acts to intensify that disposition by indulging it, feeding it, and giving it space to grow. The laboratory for creating selflessness, love of others, cooperation and empathy is the family.