I've often thought about this myself. Not just the loss of Shakespearean and biblical references from people's backgrounds, but the loss of references to several decades of English humour. Flanders and Swann, Beyond the Fringe, possibly even the more obscure parts of Python? OTOH, even though I studied Latin from the age of twelve, what's absent from *my* background are the treasury of Latin tags and allusions that educated English people had at their fingertips up to the mid-20th century at least. Can't say I've missed it at all, not knowing all of Vergil and Horace and oh god no Cicero. I can find a use for 'Quantum mutatus ab illo Hectore', perhaps, but very few people are likely to get the allusion, so might as well phrase it another way.
Must go by Bakka and get the Pratchett essays, supposing they're out this side of the pond. Weren't, last April.