> if I set a thousand users on to a website to each download a single page and then feed the information they retrieve from that one page into my AI model, then are those thousand users not performing the same function as a crawler, even though they are (technically) not one?
No.
robots.txt is designed to stop recursive fetching. It is not designed to stop AI companies from getting your content. Devising scenarios in which AI companies get your content without recursively fetching it is irrelevant to robots.txt because robots.txt is about recursively fetching.
If you try to use robots.txt to stop AI companies from accessing your content, then you will be disappointed because robots.txt is not designed to do that. It’s using the wrong tool for the job.