Thing is that there is nothing inherently bad with "theoritical stuff". The reason it works in practice is because it is sound in theory in the first place. It's just that colleges tend to stop at theory without showing you how it applies or how we are supposed to apply it in physical reality. Go through any college course and most of it is about mathematical formalism (things like your NP completeness or in physics - strings theory), rather than basing views on reality. That is what i think is wrong with most college courses.