New user here, and admittedly am primarily an AFL fan who enjoys the NRL and is growing in interest in each year. Fui Fui Moi Moi was my king!
I am from Perth and I think that a strong NRL team would do great attendance and interest here. We get around and support teams from other codes other then AFL when they are doing well. We had the Glory sell out Optus Stadium when they were firing and the Scorchers & Wildcats are the most successful teams in their respective competitions. It seems to me that NRL fans are looking for a million reasons why not to expand outside the bubble when the reality is it there is enough interest to carve out a space in the sporting landscape for sure. We would get behind an NRL team and they would do healthy numbers in my opinion. Interested to hear thoughts, I don't know the landscape well so I may be completely off base.
I think you summed up the main concern when you said Perth's residents support teams that are successful. The BBL, NBL and A-League aren't glamorous competitions by any stretch of the imagination and aren't hard to dominate. None of them attract the best players from their respective sports. Perth Glory were successful in the dying days of the NSL, but have struggled in the more professionally run A-League. There was no Sydney FC, Melbourne Victory, Western Sydney Wanderers or Brisbane Roar in the NSL to prevent the Glory from dominating a dying competition. Clubs like Sydney FC, Melbourne Victory, Western Sydney Wanderers and Brisbane Roar drew significant investment from rich businessmen that was unavailable to their predecessors in the NSL.
Perth dominated the NBL for 35 years after its boom period in the early 1990s. There was a period in the 2000s when the NBL had no teams in Brisbane and Sydney. Melbourne struggled after the early 1990s, losing the Tigers, Giants, Magic and Dragons.
Attaining success in the NRL will be be a tough task for a Perth team. It will be competing with powerful clubs from Brisbane and Sydney that generate up to $40m from football operations and gaming, and; receive strong financial support from their respective state governments to build world class high performance training centres and stadia. Clubs with the best resources generally have more success recruiting marquee players and acquiring the best juniors. Perth won't have many local juniors to work with and will have to convince Queenslanders and New South Welshmen to travel to the otherside of the country. It will be expensive scouting these juniors and difficult to convince them to choose Perth over the Broncos, Dolphins, Roosters and Panthers. The Dolphins have the potential to become a junior nursery just like the Panthers. If the Brisbane Tigers get a licence then they'll have southern Brisbane, Logan and Ipswich within their nursery.
The other roadblock standing in Perth's way is the Melbourne Storm. Juniors are keen on moving to Melbourne because it's a global city and the Storm have been a juggernaut since their inception.
I don't doubt that a Perth-based team can survive and have a smallish fanbase of 13-15k. I just cannot see it being like the Melbourne Storm, Perth Glory (NSL), Perth Wildcats or Perth Scorchers.