Forget ANZ Stadium as it's a monstrosity that never should cater for club footy, however, using the example you've used, Allianz Stadium is different.
14k from 30k is almost half full, and the vast majority would be (as you say) located along the sideline,
This hypothetical scenario improves within the confines of a suburban ground.
Rugby League was not meant to be viewed behind the goalposts.
Don't forget the extra 2 metres as Mary says we would win many more games if the fields were 98 metres long.
Any way Jimmy, when I go the the games which I go to many, there are empty seats all around me whether I sit opposite the 25 metre or 35 metre from the try line areas.
Netball isn't great to watch behind the posts, much better up along the sides, but even they are selling out 17,000 seat stadiums.
And EPL soccer, behind the posts is ok for a goal, but general game watching is much better up along the sideline, but they sell out.
League has a crowd pulling problem, they need to address it and fix it.
Pretty poor when even netball crowds are higher.