The article is specific to software engineers, and perhaps it's accurate within that discipline. The field is incredibly broad—ranging from writing small support scripts to engineering massive distributed systems—so it's plausible that a self-taught engineer could excel in certain areas. However, I don't believe this holds true, or is even feasible, for other engineering disciplines. In those fields, earning an engineering degree is typically a prerequisite. After that, you're free to self-teach and explore further, but without that formal foundation, it's difficult to progress meaningfully.
Side note: I think the term self-taught is often misused. Very few people are truly self-taught in the sense of starting from a blank slate and independently mastering a subject without any guidance. What the article refers to as self-taught is really just informal education—learning through blogs, tutorials, bootcamps, or YouTube University.
the definition of self-taught: having knowledge or skills acquired by one's own efforts without formal instruction
I think you're engaging in some weird goal-post moving. The phrase exists to highlight the difference between "i had someone else tell me all the things I should know and let them give me that knowledge" (e.g. college or a boot camp) and "i went out and found resources and did experiments so that I could learn what to do without that guidance". It is not "i discovered everything for myself by first assuming some principles and then rebuilding the whole field for myself".
Side note: I think the term self-taught is often misused. Very few people are truly self-taught in the sense of starting from a blank slate and independently mastering a subject without any guidance. What the article refers to as self-taught is really just informal education—learning through blogs, tutorials, bootcamps, or YouTube University.