If I've not posted this before, I think a lot of us used to be 33 LP play-by-ear learners who picked up some habits along the way that made it more difficult for younger students to practice correctly than not. Then, as cassette tapes made the scene, some of us gravitated towards that.
With the advent of YouTube and apps that slow down and loop/repeat musical parts so as to ease learning, this has also increased the number of people who are playing with more proficiency, and at an earlier age, than their respective counterparts who gained the same learning at a later stage in life.
So when I hear little Johnny pulling off lightening-fast arpeggios and tapping technique, I don't automatically suppose he's gained this knowledge from a teacher. Perhaps his own tenacity a student of self-taught guitar, but a student, just the same.