Look those who keep advocating or suggesting relocations of Sydney teams to elsewhere constantly overlook the one issue, namely the respective clubs' finances. For most Sydney based NRL teams, its financial bed rock is its leagues club. They tend to underwrite the operations of the football club. In fact some of them have it that the directors of the leagues club control the football club, or some have it that the football club appoints some of the directors of the leagues club.
As such, if you moved the football club out of the city of that leagues club, you start undermining the club, as eventually, you will get people advocating for the leagues club to sever its financial ties to the rugby league club. I suspect people would, in the longer term, resent money being spent on an organisation nowhere near them.
Hence teams like the Tigers (Wests Ashfield), Bulldogs (Canterbury Leagues), Eels (Parramatta Leagues), Penrith (Panthers Leagues), Roosters (Easts Leagues) would be committing financial hari kiri if its links to its leagues club was severed. You can say "oh but they will earn new corporate support, new fans" etc etc, but that will take quite some time to grow to replace a revenue stream, and also an asset bedrock that the leagues club provides for those clubs.