IIRC in the 1990's Perth were regularly selling out the 8,200 seat Perth Entertainment Centre (located literally a stone's throw from the Perth Arena), and before that they were getting full or close to full house crowds at the Superdome (Challenge Stadium). So the support for the Wildcats has been there for a long time. The people in WA generally have an "Us vs Them" mentality with the rest of Australia and it shows in their support of national league sporting teams. The Eagles, Dockers, Glory and Wildcats regularly get crowds that a few other's only dream of.
NZ's support has steadily grown from the time they started, to the point where half of their games are now played in the 9,300 seat Vector Arena because the NSEC isn't big enough. It helps that they're currently the best team in the NBL. Another thing that helps is the inbred "Beat Australia" mentality of the Kiwi's. Other than the All Blacks winning the World Cup, the Kiwi's like nothing more than beating us Aussies. The Breakers are doing that and they're loving it.
Have to agree with natwhereyouat. From what I've heard the Tigers support base is limited by a few factors. Because they also play locally in Melbourne, those associated with or who support other teams won't support them. There are also those who formerly supported other Melbourne based NBL teams like the Magic/Titans and the Giants who will never support the Tigers just because they're the only team representing the city in the NBL. They hated the Tigers back then and still do. All of that is a legacy of an NBL team being from a local club rather than a composite team.
Nat also hit the nail on the head about Wollongong. Because the St George-Illawarra Dragons play half of their games at WIN Stadium (with generally more than half the team also being juniors from the Illawarra district), they dominate the local sponsorship market. With the media coverage that the Dragons get compared to the Hawks, sponsors know that they will get a lot more bang for their buck. And unlike the NBL, every single NRL game is televised, either on Fox Sports or nationally on Channel 9 (plus, FWIW, the games are also shown in NZ and the UK). Kinda makes it hard for the Hawks to attract the big dollar sponsors when they've already given their money to the Dragons.