People have chosen not to have children for at least as long as people have been writing down their thoughts. Most cultures throughout history have a monastic class of some sort, who renounce many aspects of conventional life to pursue other aims. There are myriad ways to live a significant, meaningful life without children. If you cannot think of a worthwhile use of your life that is not focussed on either your own material enrichment or raising your own progeny, that is merely a reflection of your own worthlessness.
Saying "I regret having children" is one of the most taboo sentences in our society. Until we address that taboo, we are unlikely to find an honest answer as to whether having children really is a source of fulfilment.