It's quite key to the legal strategy of all the LLMs that they do not need a license for their input data. So if they want reddit data they'll just scrape it (which is also legally protected). And if they do need a license then reddit does not have one to sell to the AI companies, at least for most of the text on their site. I don't believe it's a reasonable strategy for any platform (except maybe marketplaces like shutterstock) to attempt to charge money for data for machine learning.