I've been interested in this concept for a little while, whether reading dots is necessary to growing your musical knowledge.
I'm not necessarily convinced (and willing to have my mind changed) that the ability to read actually adds to a theoretical knowledge-base, I feel it's largely an alternative to playing by ear, be that for purpose of training or learning etc.
There's certainly an argument that if you can't hear a recording of the piece of music, or no-one is around to show you a particular musical concept, then it is clearly helpful/necessary should you want to play that same music, but in a modern-day context, I don't think it's needed for furthering other theoretical learning.
Now, of course, it is of massive importance if you want certain gigs, or to teach to a certain level, but that's performance, not learning. And of course, those who embark on a more academic musical journey will likely be able to read as it's part of the syllabus along with all other theory. But that is simply the western academic musical tradition.
So do I think people should learn to read music? Yes of course, it will open doors to you no-doubt. But I do think you can achieve an extensive harmonic understanding and wider theoretical knowledge of music without reading dots, I don't believe them to be mutually exclusive.
Take language, it is quite possible for someone to talk well, to understand the words and how to manipulate them without being able to read or write. Of course, most people who are good at one are good at the other because that is our academic tradition, but they are quite independent skills assuming the appropriate learning structure is in place (demonstration over reading text books etc etc).
Interesting topic!
Si