What do you read in English? I would suggest that achieving deep fluency in a language requires experience with the greatest and formative literature of that language.
The English language is changing. Nobody speaks like Charles Dickens, John Buchan or Emily Bronte. Even TV shows from the 1970s are wildly out of date.
1. it assumes that the references to the writings of Charles Dickens, Emily Bronte, William Blake etc. etc. do not litter the linguistic landscape and that people could not improve their understanding of the language by picking up on those references (John Buchan maybe not so much)
2. that there are not levels of usage of the language where these references are required (which I called deep fluency), one can certainly be fluent and argue points, but not know how to adequately poke fun at Alan Simpson's quote of "Who steals my purse, steals trash" without some familiarity of Iago.
3. Finally it assumes that there will never be any conversation or situation in which there will be people familiar with these references, and that they would do anything like sprinkle those references throughout their speech, as a sort of intellectual spice. Widely read people may often do this and, as like seeks like, their acquaintances are probably widely read as well, so it can be helpful to know what these people are talking about.
If you cannot recognize the reference, you cannot respond in kind.
At any rate I thought it a truth universally acknowledged that some phrasings don't go out of style, and must be in want of insertion into any discussion they could possibly fit.