Certainly the various interests do have differing focii and agendas. However look at the recent removal of overflight restrictions for permit aircraft. Inspite of different interests the various parties overcame their differnce and got a positive result.
The GA Alliance is based on the same principles. Perhaps what we really need is organisations like AOPA to be a bit more honest and simply admit they are a trade lobbying body when push comes to shove?
At the end of the day BGA, LAA and BMAA have fairly clear objectives. So do the smaller organisations such as PPL/IR. The cameleon often appears to be AOPA.