A junky single-piece lens won't do it, you can't correct everything in post-processing. Information that is lost is lost. But there are corrections which can be well made computationally, like lens distortion. As a consequence, there are several modern lenses which trade more distortion for general improved sharpness. The distortion then gets corrected digitally. As a consequence, you do get improved picture quality vs. what would have been possible in the same package otherwise.