Having AFL on leading in to the Sunday night news would be a ratings disaster. That's why they have the NRL on at this time. They get a good lead in, viewers stick around for the news, then stick around for Backyard Blitz or whatever they have on after the news these days.
The whole thing about Live TV coverage reducing crowds is a myth. In fact in the new Cricket broadcast deal games will now be on live against the gate. It won't make any significant difference to crowds, and will make a big difference to increased TV ratings.
We do need a Sat arvo game, mainly because AFL gets a free hit at that time. Sat night news and Sports Tonight gives much more time to AFL because they have a game to report on. But without a game having been played, NRL misses out.