To be fair Auckland, Perth, South Queensland, and Illawarra were all f**ked, they were all basically flat broke and without massive investment (that honestly the NRL couldn't afford at the time and News wasn't willing to part with) they all would have folded anyway.
NZ got lucky cause after Auckland folded Eric Watson came in with bags of money and successfully negotiated with the NRL to start a new club in NZ, but with the exception of South Queensland (though there are other reasons why they were screwed) the chances of that happening for any of the other clubs, let alone of all of them, is slim to none.
So yeah realistically the NRL got very, very lucky with the Warriors, and Perth, South Queensland, and Illawarra were done and dusted...
More to the fiasco than that! South Qld were ostracized by the Broncos News Ltd connections. If News ltd were genuinely proactive and well meaning they would have backed the clubs you speak of with an assurity that they enjoy a strong media coverage relationship onto the distant future. The potential was there however the decision makers were not making/intending to create/make decisions for the advancement/growth of the code and longterm business growth.