Not everyone who has taught in a college is an appropriate choice to teach K-12. As a parent, I would certainly be disturbed by your repeated insistence that your subject is not particularly important to a student’s future. I don’t care what the subject is, that is not the attitude I want to find in a teacher. If your subject isn’t that important, then quit teaching it.
As for illiteracy, it truly is an evil, since it isolates the one who cannot read from such a vast amount of what the rest of humankind feels, knows, and believes. You have that absolutely right. Eradicating that evil, however, will not automatically eradicate low-skilled jobs. Someone has to do them, those people and their labor have intrinsic dignity, and I hope we don’t teach our children that they’re going to college primarily so that they won’t have to share the poor lot of those who do the manual labor that keeps society running quite as much as the labor of the educated. If we do, we’re flunking them in religion.