For one thing, having children and raising them to know the Lord and make a difference in their world is one of the best ways to make the world a better place. Children are an investment in the future. You can complain about how bad things are or you can do something about it. One of the most effective things you can do to change your world for the better is raise great kids who grow up to contribute to society, help the needy, demolish bad arguments against God and Christianity, bring others to Christ, and raise more children to do the same.
It's also a rather short-sighted view to think our era is so much worse than all of history. While our society is certainly in decline, we still have far more freedom, wealth, health, and knowledge of God than most of the people who have ever lived.
Countless generations before us managed to bear and raise children in a truly terrible world. Many feared that their children would die of disease or wondered whether they would be able to feed them tomorrow. Surviving to adulthood was an accomplishment. Mothers have borne and tended children in slavery, in the midst of war, as victims of rape, as refugees in a land not their own, through famine and plague, hard-labor and many tears, and they did so despite their suffering because their children were a hope for a better tomorrow. Even those who had a relatively good life with no wars or plagues or slavery had it tough. Everyone worked hard, including the children. Many had little time for education. If they could raise children in such times, who are we to complain or lose hope when we live in far more wealth and luxury than the kings of their time?
Not only do we have material wealth the people of the past never would have dreamed of, we also know that the King of Kings has come and given us new life. We have a promise from God Himself that if we have faith in Christ, heaven will be our home. We have the spirit of God living inside us to help us avoid sin and make wise choices and we can share our faith with others so that they have the same hope.
Every child in a Christian home is a tangible hope that life will go on, more people will be taught about God, and more people will be in heaven. That's far more important than an idealized and impractical notion that children should only be born into the most perfect of situations. If our ancestors had taken that view, none of us would be here.