To become a good programmer you need either a gift (which some young people have) or experience -- lots of experience. A CS education gives you a good foundation, but you still need to learn so much more: software engineering practices, lots and lots of details, a variety of programming languages and their huge libraries, mistakes mistakes mistakes (so you can learn the patterns, so you can spot them in code reviews, so you can avoid making them again, ...), full-stack-ness (so you can scale, so you can foresee problems before they strike), ...