Nope, I can't say I did go there.
As for what else you said, maybe there is some credence to your view the +j on #Teens. I wasn't for or against, I just went with the flow and in any case, it's ancient history and I'd almost forgotten it ever existed. Still, what commercial organisations see as new ideas is usually something that the general populus disagrees with. I doubt this in itself is responsible for any exodus of users as there was a channel made specifically for mIRC users and +j was only ever experimented with in two rooms, one of which held it's ground.
Disgressing for a second, don't forget that NineMSN went from IRC to Webchat and kept most of it's userbase.
Back to the subject at hand, remember that the only well-known network that has made a significant growth spurt in the last two years is Quakenet and they largely did it on the back on the fact that Dalnet got hammered into the ground. The other three of the Big 4: Efnet, IRCnet and Undernet have not grown or declined in that time and hover around the 100,000 user mark as they did a long time ago.
In my view I have to say that I am surprised that Bigpond still run IRC. If you had any idea of what they spend on it then you probably would too. I'd tell you only that I am not allowed to though I can say that it's certainly more than a schoolkid's playlunch money.
At the end of the day you can't assume that the policies of any one network is at fault for a decline in the overall popularity of IRC. All networks, from where I stand, have a failry uniform set of rules and expectations. Rules like advertising, abuse and war games are usually mentioned first. I don't speak for ANY network when I state that I understand why those rules are in place. If I was a network owner I would expect much the same sort of thing.
The other thing is that it is not generally accepted in the eyes of many that big is best. Quakenet for instance has the most disgraceful and lacking Services, if you could call them that and they are the largest network by almost 2:1 as far as the number of users is concerned. Efnet, overly conservative and extremely disorganised, has no Services at all and beats it's chest over some stupid function that allows people to regain ops in their rooms, subject to the person making the attempt meets certain guidlines. If they'd just find some Services compatible with their IRCd and kick it in the guts then they wouldn't require all this stuffing around and there wouldn't be so many channel takeovers there.
What has to be appreciated by all is the cost of providing IRC to us. ISPs devote a fortune to it every year and it goes largely unappreciated. It is a free service and chews up bandwidth and at the end of the day, IRC is probably the most abused service on the Internet. A day doesn't go by without most networks being hammered with DDoS attacks. Combine that with endless griping about rules and you soon get the idea that there is not much incentive for ISPs to continue providing IRC or funding the chance for others to provide it on their behalf.
One thing I am yet to see is any network owner complain about a decline of users.
One safe bet though is ignoring Starbucks Mafia who seems to think that Internet = IRC when he quotes all those meaningless figures which have about the same influence and standing as a political opinion poll on "Who is the better Prime Minister?" I would say that most Internet users don't even know what the hell IRC is.
