Some really good black blues musicians in the past played entirely by ear. Don't know if it's still true.
Most people these days can identify different keys -- of course -- this is in C or G and most know what other chords go with, but I certainly couldn't tell you by numbers of sharps or flats what all the keys are.
I'd think it would be entirely possible to learn to play blues progressions really well without knowing the names of any of the chords.

There are huge differences in the amount of "head" knowledge in good musicians.

Consider that Paul McCartney was originally invited to come to a session with John Lennon's band at least in part because he knew how to tune a guitar -- something John and co didn't.
Blessings,
Barbara