This organisation is not as open as it should be. Voting membership costs a lot of money (non-voting isn't great value either).
It should really be reformed to be more transparent. My personal opinion is that Cadence is over-represented and the users very under-represented. The result of which is that the problems that come to the comittees looking for solutions do not get handled properly. E.g. hardly any analog circuit or mixed signal designers turned up during the Verilog-A/AMS meetings, so the Cadence representatives would say "users won't want to do that" if they didn't want to implement something - and it was rather hard to argue with them.