Spoken languages are like that too. A 3 year old doesn't know what verbs are. They just speak.

Another interesting thing is how people forget their path to personal journey regarding learning. "I did `y`, but you should do `x` because now that I look back I should have done `x`." "But, but, you did `y`! "Yes, but `x` is the way to go."

You mentioned musical instruments: great topic. The very best musicians have always been around music, sometimes not even being able to read music. There is no clear path, the only clear thing about this is the time + effort regarding learning something well: just have to put in the time.