I’m not sure it’s the Raiders. That could affect fan engagements more so. Bigger city but will the Broncos hurt Rugby in Brisbane now? I think Leagues overall development is far better though. If true about the Raiders, their recent popularity and basic competitiveness (other than this year 8th is their highest finish in the last 5 seasons) Would have a bunch of players coming through to maintained competitiveness for the next 5+
I’ve just seen a decline in the standard of sides that come to Sydney from the traditional Schools like Eddie’s, Marist, Grammar for the last decade. Was never the same standard but it was a contested game between 1st, 2nd XVs but now I think some would be 3rd XV and the best probably a 2nd XV standard.
The major difference between Brisbane and Canberra is that Brisbane (or SEQ more accurately) is still a net exporter of talent, and there's more than enough coming through each year for both the Reds and Broncos, at least in a general sense. That doesn't look like the case for Canberra, where the population is significantly smaller - about 1/6th of Brisbane's. To put that in real terms, Brisbane has about as many kids 14 and under (~450k) as Canberra has people total. Obviously they're not all rugby players or will be candidates for a super side, but we're talking completely different scales where the limitation in Brisbane is as much opportunity as it is talent supply. In that context than success in either code should help the talent pool for both, drawing young kids into rugby in general, from there plenty of the best ones will end up being exposed to both games and can be picked up by either.
On the fan side I don't actually think the Raider's success hurts the Brumbies too much, there aren't that many people making either or decisions and the Brumbies have been going well consistently so shouldn't suffer in comparison. I do hold a similar view for Brisbane though, were the status quo is fairly stable and the fight for column inches isn't new (dual Broncos and Lions success might be more of an issue though). Cost of living issues may be changing that slightly, but there are opportunities too - Reds and Dolphins did a dual ticket this year and I think the Brumbies and Raiders might have done the same?
If I'm right about the Raider's (relative) success hurting the Brumbies development pipeline then it does follow that impact on development is going to lag a bit - I'm mostly talking about the 19 and 20 seasons here (so a little outside of 5 year) where they ran 4th and 5th and seemed to capture the local interest with the whole Viking clap thing. That's when a bunch of ~10 year olds might have been lured one way or the other, and we'd be just starting to see it now in the under 16s. This is wildly speculative on my part though, I have no idea what the local scene has been doing. AFL might also be eating into the talent base there, I get the feeling they've been starting to snap up a bit of the talent via GWS pathways.