If you want to go back to the start, look up MICR. Used to sort checks.

OCR'ing a fixed, monospaced, font from a pristine piece of paper really is "solved." It's all the nasties of tue real world that its an issue.

As I mockingly demonstrated- kerning, character similarity, grammar, lexing- all present large and hugely time consuming problems to solve in processes where OCR is the most useful.

MacPaint had that in 1983, but it never shipped because Bill Atkinson “was afraid that if he left it in, people would actually use it a lot, and MacPaint would be regarded as an inadequate word processor instead of a great drawing program” (https://www.folklore.org/MacPaint_Evolution.html)

Also shows a way to do that fast:

“ First, he wrote assembly language routines to isolate the bounding box of each character in the selected range. Then he computed a checksum of the pixels within each bounding box, and compared them to a pre-computed table that was made for each known font, only having to perform the full, detailed comparison if the checksum matched.”

I've worked extensively with Tesseract, ABBYY, etc in a personal and professional context. Of course they work well for English-language documents without any complexity of layout that are scanned without the slightest defect. At this point, based on extensive testing for work, state of the art LLMs simply have better accuracy -- and an order of magnitude so if you have non-English documents with complex layouts and less than ideal scans. I'll give you speed, but the accuracy is so much greater (and the need for human intervention so much less) that in my experience it's a worthwhile trade-off.

I'm not saying this applies to you, but my sense from this thread is that many are comparing the results of tossing an image into a free ChatGPT session with an "OCR this document" prompt to a competent Tesseract-based tool... LLMs certainly don't solve any and every problem, but this should be based on real experiments. In fact, OCR is probably the main area where I've found them to simply be the best solution for a professional system.