Speaking as someone in the games industry, I disagree with your take on portfolios. For reference, when I graduated college back in 2015 I had a portfolio of games, a successful and reasonably popular game mod and a bunch of relevant classwork. None of that even mildly got my foot in the door at any gaming companies, big or small or otherwise. Also of note, many software companies force you to sign an assignment of inventions agreement or a declaration that says you will not work in anything remotely related to software in your free time, which heavily restricts your ability to add to your portfolio.
What did help me however, is that I got a job at a smaller company working on software and then leveraged that professional experience into a job in the industry. That initial job I got was because of my computer science degree.
The importance of a CS degree was the stuff I learned across the degree, not stuff that was necessarily directly CS-related. Physics and math classes for example I did horrifically in as well, but those concepts I picked up have been useful to have in my toolkit.