The Bajorans are a civilization that had spaceflight in the 16th century. Their science is plenty advanced. It's just that their priorities haven't been geared toward expansionism. They have a good understanding of the physical universe, but they don't see the need to apply it toward the same goals that Federation/human society does.
By analogy: Two people can go to the same college and take the same basic classes and learn the same things, but one may be motivated to specialize in aviation and become an astronaut while the other may be inspired to pursue a master's in history and spend her life studying the past in libraries. The second student doesn't have less knowledge, just a different set of interests.
By analogy: Two people can go to the same college and take the same basic classes and learn the same things, but one may be motivated to specialize in aviation and become an astronaut while the other may be inspired to pursue a master's in history and spend her life studying the past in libraries. The second student doesn't have less knowledge, just a different set of interests.