I always thought St. George and Souths were a better fit, bordering each other, similar demographics, socio economics, long rich history, could have kept the red V, just change the white to green.
Same with Cronulla and Illawarra, bordering each other, similar demographics, socio economics, shorter history, without much success.
But it is all too late now, Souths after refusing to merge/JV ended up selling out to a film star, Cronulla have emerged from close to bankrupt a couple of times, to a financially viable stand alone club, and it is probably much harder to discontinue the JV, than to keep it.
As it was back then --> too hard basket