I'm not really sure why the NRL are bringing up relocation like they are.
Realistically a 9th game will be worth quite a bit to the NRL cause it's more content to sell, where as unless you've got people willing to subsidise the relocation, such as local governments, new owners that want to relocate the club, broadcasters that want teams in specific markets, etc, relocation can actually be a very expensive enterprise, so it seems strange to me that Greenberg would be talking up relocation given the NRL's current situation and the almost certain fact that even if Fox and Nine don't want to pay for the extra content there're definitely people out theire that would be happy to pay handsomely for it.
All of that leads me to suspect that the NRL, or at least Greenberg, realise that they really need to have teams in at least three or four 'new' markets now if they are going to compete in the pro sports market long term, and they think either that selling two more games at once to broadcasters would be a big ask (which it probably would be) or that there isn't enough talent to support that much expansion all at once, so they are considering other methods to fast track expansion so they can get a presence in those markets as quickly as possible, which is leading them, or at least Greenberg, down the route of floating ideas like relocations and BS like 'you don't need to expand to markets to have a meaningful presence in that market'.
Anyhow, there'll be some interesting times ahead to say the least, but I really hope that they don't come to the conclusion that it's better to relocate clubs to Perth and Brisbane then expand to those markets... Both Perth and Brisbane have multiple groups ready and willing to pay the NRL for a license, so if you're going to relocate clubs those aren't the places to relocate them to.