Another thing to consider is a lack of an independent lower tier competition, i.e. like the NCAA players feed into the NFL draft. It alone is a profit making business, so has no ties to the NFL. Most of the comps where the NRL would be drafting from, do have ties to existing NRL clubs, even some of the country regions have tie ins (like the Panthers at Bathurst).
There was talk a while back of a draft using the U20s as the talent pool, but they were going to let the teams tag the "top 5" that they had exclusive rights too, with just the remainder going into the pool. I imagine that once the top 5 are removed, there wouldn't be a lot (of talent) left over, from the remaining players. Anyway, that didn't happen.
Before any sort of draft is revisited, it would need to be signed off by the RLPA, so that no challenges are made. It is in the best interest of not only the struggling clubs, but the sport in general, in my opinion, but probably not the players, so this would be difficult to achieve.