It's probably difficult for him to issue it all strictly on time, since he's a solo indie dev. He does it all alone and he probably has a lot if other things going on in life, so a slight delay is not a big deal.
Ofc, this is just me speculating
He must be a truly incredible genius if he does everything on his own. I have experience writing a few books in the past and it is really difficult to write something good and something that will make the reader think or laugh. Although the DEV did not do a perfect h game, but he definitely did a much better h game than average. Each character has their own character and past, and they are well thought out.