Having been a student with good and bad teachers, I can see your point.
However, many of the things that you are being taught (at least I hope this is still the case) that don't appear to be needed for the "job" are actually important because they are needed for the understanding of the background for why and how the "job". The failure of teachers that we faced as students was that the reasons for learning something were often not explained and only became obvious when learning about other subjects in later years. Having the relevance of the knowledge explained to us would have made it easier for us to learn.
One of my favourite examples was the subject of Karnaugh maps (or K-maps) which is used in logic circuit minimisation for small circuits. We learned all about and didn't use it again for the rest of my engineering undergraduate days.
However, a number of years working with a colleague on trying to solve a particularly pernicious software problem, I asked him why he hadn't used the concept of "don't cares" in short-circuiting the logic mess that was required to solve the software dilemma we were facing. He had never heard of the concept as he had never been taught about K-maps in his undergraduate programming course.
One he understood the concept and it didn't take him long, he was able to write 5 lines that solved the problem, instead of the hundred's that he had already had written (with many more to follow) to test for the problem throughout the program.
I have been surprised at how often over the years, where theoretical knowledge or other knowledge has come to the rescue in finding a solution for specific real-world problems, even though it has (on the surface) no relevance to the job at hand.
I have worked with some very smart people over the years (much smarter than me) who have been stuck for a solution because they didn't have that "irrelevant" piece of knowledge from their undergraduate days, but I did and so a problem was solved.
The one piece of advice I will give you is to learn as widely as you can so that you basic knowledge base will be broad enough for you to keep adding to as the years go by.