Could be part of an attempt to drive crowds, memberships and potential broadcast deals.
Having reserve grade teams specifically aligned to an NRL club will increase brand awareness of those teams and may mean fans start to take more note of that competition.
If that was the case you'd have historically seen a consistently higher average attendance for the NSW Cup teams run by NRL clubs. As far as I know crowds aren't recorded for most NSW Cup matches, but in my experience that simply isn't the case.
It's also my experience that the Qld Cup would have a significantly higher average attendance than the NSW Cup, and until this season it's been completely made up of independent clubs affiliated with NRL sides, as opposed to the glorified reserve grade sides that have made up the bulk of the NSW Cup teams.
Reserve grade was never as big a draw as some people like to remember, and it was well and truly dead by the 90s, and even the earlier 80s in a lot of parts. In this day and age you simply aren't going to get the average punter to show up for reserve grade before the NRL, and PVL and his mates are totally out of touch with younger generations and the realities of the modern market if they truly believe otherwise.
Most blokes would rather hang out at the pub watching the earlier NRL game than get to the ground early to watch the reserves .