User blog comment:SayuriDarling/The Hidden Oracle Official Discussion/@comment-26658481-20160112184726/@comment-1515612-20160112194148

I think in BoO we could all clearly see that RR was trying to do something with Apollo being punished and leaving that as a giant cliffhanger. He probably had and idea of doing another CHB one, but wanted to get the Norse book off and running.