Kids that start CC threads and then don't respond to posts. What's up with that?

There is no obligation to comment at all on an OP’s thread, so it’s never really a “you problem” for posters. It is, IMO, the responsibility of an OP to check back. And it requires little effort to acknowledge (check “like” or “helpful”, or simply say “thanks”) responses. After all, the OP created the thread.