Well that's just blatantly rewriting history to an egregious extent...
There're is two big reasons (among many) why Norths and Balmain couldn't be as strong as Souths currently are (and Souths current success isn't sustainable long term anyway...), because Balmain are flat broke (if they were solely responsible for a club it would have folded a few years ago now), and because their presence in the competition would put further pressure on an already over saturated market which would further destabilise all the Sydney clubs making it even harder to sustain a club within the market as they all fight over the limited resources, which would create a sharper divide between the haves and have nots over time. Something about Balmains' recent business dealings tell me that they aren't coming out on top in that struggle to become a have, and the Bears being based on the CC and effectively starting from scratch in building a new fan-base would spread themselves to thin (trying to appeal to everybody and succeeding only in appealing to nobody) making them a smaller and less attractive club for sponsors and the such to back.
Any talk of more teams in Sydney (or really NSW ATM) is madness and would only lead to further dividing the fan-base and resources in Sydney over future generations, e.g. at best all you'd get is 11 smaller Sydney clubs struggling to make ends meet instead of 9 slightly bigger ones, at worse you'd get clubs folding due to the added competition pushing them out of the market. However if the comp was restructured though, say the lower tiers where better supported by the NRL and where helped to get wider exposure and coverage, thus reducing the price of entry to creating a sustainable club and to maintain competitiveness, then all bets are off cause then the Balmain, the Bears, or whoever really wouldn't need to be turning over as much as the top NRL clubs to be sustainable businesses, but that is a whole other scenario.