As soon as Rusty (and to a lesser extent Packer) goes and he isn't replaced their attractiveness to sponsors and more importantly third parties will basically half, once their attractiveness to sponsors and third parties halves their sponsorship space won't be worth anywhere near what it's currently worth which is bad in of it's self but what'll really f**k them is that they won't be attracting anywhere near the third parties that they currently do.
Once third parties start to overlook them significantly more of their players wadges will have to go on the cap and they suddenly won't be as competitive in the players market as they currently are cause they'll effectively be paying overs on the cap to attract and keep players on the roster, once they aren't as competitive in third parties and thus in the players market they won't be able afford as many good players (let alone star players) as some of the competition, once that happens it's a quick spiral down, the standard of players at the club will tank, since they can't afford enough good players to compete with the clubs that can afford them they won't be as competitive on the field so their rate of success will tank, once their rate of success tanks their ability to attract and hold onto fans will tank, as their ability to attract and hold onto fans tanks their membership, attendance, and viewership numbers will tank, once they tank they'll be even less attractive to sponsors and third parties.
From that point unless something drastically changes they'll either fall into this sort of limbo that the Raiders and others like them are stuck in where they are surviving but it's borderline impossible for them to actually be competitive and successful for an extended period of time because the rules of the comp are so weighted in favour of a handful of their oppositions, or (and much more likely considering their history IMO) they'll overspend, take risky business deals, and probably cheat the cap to try and stay competitive and eventually that will bite them in the arse and they'll be really f**ked.
That is why they are reliant on Crowe (and to a lesser extent Packer) and it's why their current success isn't sustainable...
Haves and haves not's, it's probably the biggest problem with the NRL currently... And frankly I highly doubt that the NRL's interested in doing anything to change it.