Does God change? Has His plan changed? Has His morality, teachings, expectations or nature changed?
Why would doctrine develop any more? We have all the information we need, and we can’t use human logic to ‘reason’ further developments because God may not follow the rational of human logic.
Note, theology is not teachings about contemporary problems like internet porn. How to deal with these issues is very simple when we just look at how we deal with similar problems. It’s not necessary to call everyone together to deal with that kind of stuff - we all can easily extrapolate a response based upon what has been received. You might not have been planning to pursue that route, but I’ve had to have that discussion with Roman Catholics before.