I know he's throwing the figure of four stadiums out there to begin the negotiation high but we wouldn't need that. We probably only need one in the south-west and one in the south.
Roosters - SFS
Eels / Souths - Bankwest (Souths already play just 15 mins away at ANZ, it's not a huge shift)
Tigers / Dogs - Bankwest copy and paste built at Liverpool
Sharks / Dragons - Bankwest copy and paste built in the south
That leaves Manly and Penrith who are unlikely to get their current grounds upgraded as they are single tennant grounds.
Manly probably need to move to the SFS if they are going to keep up in the NRL, especially if the other teams do end up playing out of Bankwest replicas, they just won't have the revenue to stay competitive. If they don't have either enough fans outside of the Manly area or committed enough fans to travel 30 mins to the state-of-the-art Allianz Stadium then they probably don't have a place in the NRL moving forward. Both the Swans and Waratahs successfully engage fans from the North and get them to come to Moore Park for games.
As
@T-Boon has said a few times, Penrith's best chance of an upgrade is to attract women's sporting teams there and get them to commit to it being their home ground. The Australian Women's soccer team would be one candidate and the ARLC could help the cause by making it the Sydney home of women's State of Origin, the home of the Jillaroos and can even use it to host Pacific Tests held in Sydney in the future.