As a professional Desk Driver with 17 years in the business and not a Professional pilot I can see where your coming from. Nobody wants an Airlin***.not kind of forum where it's so out of control you don't see the same thread twice. I also agree that some people on here can half post some rubbish at times however the Mod's do a very good job here and most is weede out.
So before you decide, you need to consider the 2 following things.
1) If you become an elite bunch in your private forum then numbers outside would dwindle to such levels that PPRUNE would no longer be free. you may be willing to pay,but how much?
2) I and many others hear a lot of relevant information around our place of work that perhaps you don't. We also can have very informed opinions from a very different angle to yours. If you want to go into a private forum and compare each others equipment and companies because that's what you'll end up doing then fine I'll leave right now. We all have the ability to report malicous or irrelevant posts to the Mod's. Lets use that instead.