There are quite a few classical allusion examples which have become so ubiquitous that we use them without even thinking about it. I think that's particularly true of biblical allusions.
I got a reminder of this recently when I was leading a book club for the local library for teenagers.
They got stuck on a comparison between the character in the book and David of David and Goliath fame.
These kids just had no idea what the author was talking about. They had never heard the story. I just took for granted that almost everyone would know it and would, therefore, understand the allusion.