Ligatures aren’t rare and archaic.. they’re a standard part of many fonts today. I actually looked at that and didn’t think as favorably as you. Lots of mistakes all over.
To me good results is like 99%+ correct, and the ability to highlight where it’s confused.
Sorry that was meant to be two separate categories "archaic lexical paradigms like the long S" and "ligatures". I should have put ligatures first to avoid the ambiguity.
This kind of blobby faded printing is still challenging for OCR. The fact that it decided to just skip entire sections is the most troubling part for me (like seriously wtf). But the parts it didn't skip I think are quite good compared to when I use other software on the same kind of material.
I wish these things had a bit more...sanity...for lack of a better word. t769 is just ridiculous. TEcole isn't a word. Beaucoupde is clearly two words that shouldn't be smushed together. etc.
Interestingly, Apple quietly bakes high quality free OCR into macOS as a library that developers can invoke in their own software that works better than this in some ways and they just don't advertise it to end users or do anything with it at all themselves (they do on iOS but Preview.app could have had an OCR option since Catalina). It also doesn't recognize things like long S, though, so it's still annoying for old texts.
Edit: I finally got it to work. The result looks good! https://i.imgur.com/hoS4oMP.png
Though it looks like yet another OCR program that doesn't understand archaic lexical paradigms like the long S or ligatures.