What's your point?You are comparing Sydney clubs that entered the comp when it only was a suburban comp to brisbane based clubs who are entering a national (or semi-national) comp. Just because Sydney has these suburban clubs doesn't mean we should replicate the same landscape in Brisbane, but it also doesn't mean we should just rationalise and merge Sydney clubs. Sydney was and still is a much bigger and more economically powerful city than Brisbane, the national comp grew out from the local Sydney comp, that's just how it is.
Sydney is twice as big as Brisbane.
Sydney is NOT nine times bigger than Brisbane. (ie. 9 vs 1)
Sydney is NOT four and a half times bigger than Brisbane. (ie. 9 vs 2)
Sydney is NOT three times bigger than Brisbane. (ie. 9 vs 3)
Sydney's teams are not anywhere as rich as the Broncos and routinely bleed more money than they make. The Cowboys, Raiders and Storm and more viable.
As you pointed out, Sydney was a suburban competition when these teams were created. The NSWRFL chose to expand and become national and had plans to rationalise Sydney in the 80s.
Not all suburban teams are fit to make the transition to a national league. For this reason, the strongest teams should have been kept and slightly rebranded so they could appeal to more than their local region. The ARLC has done exactly this with Redcliffe, who are financially stronger than most Sydney teams. Where the ARLC has shot itself in the foot is by refusing to do it with Sydney's teams. The only Sydney teams that have attempted to grow their brand are Dragons, Roosters, Rabbitohs and Tigers. They're all much bigger now than they were in the early 1990s.
Manly and Cronulla have remained insular and are among the perennial strugglers. Both would be on the scrapheap without the annual grant.
If we stick with nine Sydney teams then you can kiss goodbye to any possibility of having teams in Adelaide and Perth. If we don't have teams in Adelaide and Perth then we risk becoming a niche sport like RU.