it used to be poets and acting companies traveled from place to place, and people learned culture and expressions from them, (Shakespeare presumed when he had Hamlet say "and who is he to Hecuba, or Hecuba to he?" that the audience would know who Hecuba was.
And those who didn't enjoyed or endured the poetry, laughed at the slapstick and dirty jokes and ignored the references. Just like they do at Bard on the Beach these days.