Being on the hiring end, it’s less out of incompetence and more of not enough time, and open source code is low signal that the candidate can actually solve problems.

If I submit some “open source” code as some proof that I can code, how do you know I didn’t copy the code from somewhere?

Also, writing code for the sake of writing code doesn’t tell a hiring manager if the person can take requirements and translate that to an automated process. It just say that person isn’t that busy and can, excuse my language, shit out code for the sake of appearing productive.

Writing code can be a hobby, sure, but that’s only a small part of a software job and no amount of open source code can tell a company if the candidate can work with others and solve problems.