I think this is a better starting point. The challenge at that grassroots level is that everything is run by volunteers. On a junior club basis, here are the junior clubs across Sydney.
https://www.sjru.com.au/club-directory/
There are maybe 20 junior clubs covering the Hills, Parramatta, Penrith and everything else "west" and "north west".
There are about 40 junior clubs covering the Eastern Suburbs, Northern Suburbs, Northern Beaches and Sutherland Shire.
There's a pretty reasonable population split between the two and the former covers a far greater land area.
It's hard to create clubs out of nothing and RA/NSWRU certainly don't have the financial power to do it without volunteers.
What they should be doing is offering free level 1 coaching courses etc.
I'm still not sure that rebranding the Waratahs would achieve anything. I just don't believe there are more than a handful of fans out there who would sign up for season tickets purely because you changed the name of the Waratahs. The concept that there are people ready to commit time and money to a pro rugby team but only if it's got a different name to the one that is available to them currently seems really tenuous to me. That sort of person that says that will just find another excuse when what they're asking for can no longer be used as an excuse.