I've known several ridiculously talented musicians who couldn't tell you the notes of their open guitar strings. Some people just "have it" regardless of their prowess in ancillary areas.
Short version. Dude could sing, play, and (especially) WRITE like crazy. He found a way to tap into the human condition and relate to millions of people before that was possible via Twitter or Insta.
So it doesn't bother me that a guy didn't know what all of the knobs and switched did on his bass. He couldn't exactly Google it either.
There was another recent thread here regarding who played bass on one of their songs. WE obsess over the tiniest little details of their music/gear/recordings. THEY didn't. They just showed up, wrote hits, played whatever instrument was in front of them, and went to lunch without giving it a second thought. WE live in the past. THEY were all about "That's done. What's next?".