Additionally, HBO is in the business of trying to get its subscribers to continue as long as possible, so making Game of Thrones fans wait at least for a new series is a good way of keeping them on the line.
The network might be trying to spacing it out, so that the new series won’t be judged against the success or failures of its predecessor.
It’s also a highly anticipated event with high expectations, so fans will probably need some time to process its contents.
A year of separation between Game of Thrones and its spinoff sounds like a smart move business-wise, as the series’ viewing statistics from last season indicate HBO will have no trouble getting viewers in the final season.