Astronomy is not about building telescopes and biology is not about designing microscopes. Whilst CS is a very important field, it could be likened to being like physics is to structural engineering. Physics study will teach you a lot about how materials behave, but structural engineering will teach you how to apply that science and build structures that will meet the requirements over a long time.
The problem with being self-taught is that you don't know what you don't know and can easily succumb to the Dunning-Kruger Effect. That is why programs are so full of bugs. The coders didn't understand what they were building, they just hacked away until something just worked (some of the time).