If you look at old math treatises from important historical people you'll notice that they use very different notation from the one you're used to. Commonly concepts are also different, because those we use are derived over centuries from material produced without them and in a context where it was traditional to use other concepts to suss out conclusions.

But you have a point, and it's not just "our industry", it's society at large that has abandoned the old in favour of incessant forgetfulness and distaste for tradition and history. I'm by no means a nostalgic but I still mourn the harsh disjoint between contemporary human discourse and historical. Some nerds still read Homer and Cicero and Goethe and Ovid and so on but if you use a trope from any of those that would have been easily recognisable as such by europeans for much of the last millenium you can be quite sure that it won't generally be recognised today.

This also means that a lot of early and mid-modern literature is partially unavailable to contemporary people, because it was traditional to implicitly use much older motifs and riff on them when writing novels and making arguments, and unless you're aware of that older material you'll miss out on it. For e.g. Don Quixote most would need an annotated version which points out and makes explicit all the references and riffing, basically destroying the jokes by explaining them upfront.