What I really don't understand is where the next generation of training material will come from. If websites stop being published and/or crawled, how will the machine continue to be fed.

Current executives think it's a problem for the future executives.

Either Google is ignoring that, or crossing their fingers and hoping that one LLM can produce data to train another one.

They have enough internet slop. The training material they care about comes from experts, not randos online. This is why Mercor and Scale are billion dollar companies.