You clearly have missed the 2 key points put forth already about
1. the Crushers as proof that solid base can be built when the league administration is behind the club
2. that Brisbane's growth as a market has outstripped the broncos membership and attendance KPIs
What's even funnier is your statement "unless you are successful within your first couple of years you will fail" seems to forget (or probably unaware) that the broncos missed the finals in their first season and bombed out first week in the next.
There is enough data to suggest that at the worst of times, a 2nd team in Brisbane would generate a crowd and supporter base bigger than a club in say CQ at their best climate, and that's enough for a successful inclusion and ongoing viability.
Look, I'll try to be as objective and fair as possible and not give you a mouthful like some other users.
1. the Crushers, as proof of success of anything, is absurd. The club was a resounding failure in every aspect and the Bombers bid seems to have posited nothing different other than "people like rugby league in Brisbane, the Broncos are a financial success, start another team, profit!!"
2. What growth? According to ABS statistics, Brisbane's population has grown by 20% since 2001. Broncos memberships in 2011 were around the 16,000 mark and in 2013 were beyond to 25,000 (that's 56%). Crowd averages were down in 2013, by a lot, so crowd average -> member conversion rates were very high. Meanwhile the Reds continue to get 30,000 a year, the Lions have the Victorians and ex-pat Perth workforce sown up and the Roar have everyone else, including, arguably, the first pickings of the bulk of the population growth (being immigrants from cultures unfamiliar with Rugby/Rugby League/AFL).
Are you actually from QLD? CQ and Brisbane's outer municipalities (Logan, Ipswich, Beenleigh) are literally 90% of Rugby League's nursery/fan base. You got to these places, you play Rugby League or nothing else (AFL is for Victorians, which we distrust and hate generally, Rugby Union for private school kids, and soccer is for "poofters and wogs").
Inner city Brisbane land prices are much higher than these areas, the demographic is richer, well-educated and generally does not support rugby league or put their kids into junior rugby league (rightly or wrongly because it's a game "played by thugs" from Logan, Ipswich and Beenleigh). Since the inception of the Broncos, Rugby Union has become a professional sport. A viable alternative for the working class and poorer demographics and not the cream of GPS schools, sandstone colleges and inner city families.
You want a slice of the pie in South East Qld?
Get a franchise in Logan, Ipswich or Beenleigh, give it its own identity, throw a 20,000 seater at Springfield and the people will flock to it.
Or upgrade Virgin Stadium in Mackay or Browne Park in Rocky for the same purpose and give the licence to Central Qld
Want to flop? Build a generic franchise (like the "Brisbane" Bombers) and try to be Broncos 2.0.