I run a legitimate website with actual people publishing content... sometimes, and I get offers from advertisers for sponsored content. If I didn't earn a living on a day job, auto-generated content farming might be something I'd go into. Morally objectionable, but it's a living.
Secondary would be to just take content from Reddit and add some low effort captions to it, then target old people on Facebook or whatever. Again morally objectionable, but there's a LOT of people who really browse the internet uncritically.