Sure the professional pathways is about developing strong professional players to feed the system, however that doesn't mean that the pro pathway has to be controlled exclusively by the NRL clubs.
We are just about the only major sport in the world that I can think of that does it that way, and it seems to me that the only reason we do it that way is for the same reason that is the root of most of the major problems in the sport; there are a handful of clubs at the top whom have to much power over the sport, don't care about the health of the sport more broadly outside of their club, and do everything in their power to try to have a monopoly over everything in the sport because they are terrified of any new competition that may arise, because that competition might erode their power over the sport.
You talk about multiple games on game day and how important it is, but we've had multiple games on game day almost all of my life and the reality has always been that 95%+ of the fan-base of the clubs that it's supposedly so important to don't give a f**k about any of the leagues but first grade, and only an extremely tiny minority are paying the price of entry to watch the lower tier matches.
I mean look at the NRLW or the Under 20s a few years back, they'd be lucky to be playing in front of more than 1k people most matches.
Linking those leagues to the NRL clubs kills their potential as commercial products, which is a disservice to them because they could be built into commercial products (particularly the women's league and the second tier), and it's a disservice to the sport because it just makes them a net cost on the clubs and NRL when they could be making the NRL a profit.
Also you say your kids become disinterested in the lower tiers when the teams aren't their team as it were, but did you ever stop to think that maybe they (and you) aren't the target audience and that maybe that is ok? Not everything needs to be about the NRL clubs and their fan-bases, and the fact that almost everything is about the NRL clubs and their fan-bases is one of the biggest things holding our sport back.
Just imagine where the sport would be right now if the thousands and thousands of fans in the bush were attending games locally every fortnight, that can't happen so long as the lower tiers are so strongly linked to the NRL.
Its interesting to see how clubs have decided its not how they want to run their professional operation
Penrith tried with St Marys/Windsir and then came back as Penrith
Newcastle tried the CC then cameback as Newcastle
Warriors tried as Auckland then reverted back to the Warriors
Souths tried as the Bears then reverted back to Souths
Canterbury tried as the Sydney Bulls then returned as Canterbury
Wests-Tigers tried as Wests and Balmain-Ryde-Eastwood then returned as Wests-Tigers or just Wests once they took full control of the licence
St George-Illawarra tried as St George and Illawarra and then Shellharbour then returned as St George-Illawarra
Parramatta tried as Wentworthville and then recently reverted back to being Parramatta
I see a trend