There are plenty of lyricists who can't play, read or write music apart from the ability to hum a tune, and the ability to feel rhythm. A common approach is to collaborate with someone who can, in order to provide complete songs.
Don't get me wrong, as pointed out in those articles, there are no songwriting rules, only guidelines. They outline the wisdom of the ages regarding songwriting distilled down. By learning the concepts, you can then choose to use them or not, and gain an understanding of the consequences of sticking to a guideline or not. All in all it helps you to produce a finished song quicker, going down less blind alleys, and finishing more of the lyrics that you start. You learn common issues to avoid, and how to more effectively connect with an audience, to lead their emotional journey, deliver your message to them etc. All good stuff. Perhaps some of our non-musician writers will share their perspective....
