Most "serious" publishers pretty much entirely stopped accepting direct submissions from authors long ago, and instead started requiring people go through agent

Most "serious" publishers pretty much entirely stopped accepting direct submissions from authors long ago, and instead started requiring people go through agents. It's mostly just been small and independent publishers that have kept accepting direct submissions, and most of them had limited resources to help aspiring authors to begin with. Agents already filter out a ton of garbage that is human written, and in my experience, take a meeting with potential clients before they read any significant portion of work as well - it would be trivial to make a discussion around AI usage part of that meeting.