That doesn't explain it IMO. That data is already freely available and LLMs don't need the latest data. So data scraping for AI makes up a miniscule amount of API usage.

I think it has more to do with inflation. Investors aren't putting their money into risky tech companies as much, and so these companies (twitter, reddit, etc) have to prove they can be profitable for once, and they probably are going to fail to do this. It does mean we can't have nice things for free anymore like API access.