I have less than 2 years of college left and I still don't know what to focus on. But this is not about me, this is about being a future developer. I realize that questions like "Which language should I learn next?" are not really popular, but I think my question is broader than that. I often see people write things like "You have to learn many different things. Being a developer is not about learning one programming language / technology and then doing that for the rest of your life". Well, sure, but it's impossible to really learn everything thoroughly. Does that mean that one should just learn the basics of everything and then learn some things more thoroughly AFTER getting a particular job? I mean, the best way to learn programming is by actually programming stuff... But projects take time. Does an average developer really switch between (for example) being a web developer, doing artificial intelligence and machine learning related stuff and programming close to the hardware? I mean, I know a lot of different things, but I don't feel proficient in any of those things. If I want to find a job as a web developer (that's just an example) after I finish college, shouldn't I do some web related project (maybe using something I still don't know) rather than try to learn functional programming?

So, the question is: How broad should a computer science student's field of focus be? One programming language is surely far too narrow, but what is too broad?