And as soon as the poem was published, people started writing explanations for the difficult bits. Dante's son Jacopo wrote a commentary in 1322, Graziolo Bambaglioli wrote another in 1324, and by the end of the 14th century there were at least fifteen. This shows that the poem quickly found an audience that was not familiar with all the references.

It think it's a bit of both. Dante moved in high circles, particularly after he was exiled; and as an intellectual at court, he was effectively tasked with being an entertainer to his masters (which he didn't like, but had to accept to survive). In that context, creating work that requires active engagement from the audience, basically quizzing them around historical and literary knowledge, would have been of great value - and of great fun. Imagine people chatting around a fireplace or a banquet table, and Dante reciting a small verse - challenging someone in the audience (particularly other intellectuals he'd be sharing favours with) to go "I know! He's talking about such and such!". And when it came to the then-contemporary popes and rulers, everyone would laugh at the satirical tones, like you would with a stand-up comedian delivering a joke about "the orange man".

Comic book folks might be familiar with "The League of Extraordinary Gentlemen" by Alan Moore. That follows a similar approach; most people will recognize enough of the main characters to follow the story, but very few will get them all - which is why third-party commentaries and companions exploring them, have been pretty popular.

But he does not give notes for Abel, Noah, Moses at 4.55; Abraham, David, Israel and Rachel at 4.58; Homer, Horace, Ovid and Lucian at 4.88; Aristotle at 4.130; Socrates and Plato at 4.133; Diogenes, Thales, Anaxagoras, Zeno, Heraclitus, and Empedocles at 4.136; Dioscorides, Orpheus, Cicero, Linus, and Seneca at 4.139; Euclid, Ptolemy, Hippocrates, Galen, Avicenna, and Averroës at 4.142.

So Jacopo, at any rate, thought that readers might need help with mythological and historical references, but not with biblical and philosophical; or maybe he thought it was clear enough from the text that Diogenes, Thales, Anaxagoras, etc. were pagan philosophers. But Guido da Pisa's 1328 commentary has detailed notes on all of these. So there must have been readers who wanted more information on these figures.

And I am adding that while always interesting and rewarding for those that are obsessed with a work, "getting" the references in Dante's Comedy or any other work of merit is not the point, and they are not all that important in the work.

And further, since I am near the subject, I am engraving my personal ad hominem, that it is the characteristic mark of a certain class of readership (which I hold in low regard) to fixate on which 7th century monk in which manuscript first introduced some mentioned doctrine before having (and never-to-have) attempted to commune with the work itself.

A Neolithic person who made it to 20 had a good chance of making it into his 50s or 60s, but a serf’s odds weren’t great and a day laborer’s were near zero.