I have been to SQL standards committee meetings. Actually, the process is quite relaxed and open, and there is friendly cooperation across vendor lines, once you find your way in. So I don't believe the conspiracy theories. And there are no requirements about secrecy of the proceedings. You can read up on everything if you become a member of the working group or even just a temporary guest.
The main problems are (1) ISO politics and (2) the effort required to do the actual work.
First, the participants don't like the ISO politics either, but they're there, so what are you going to do? ISO has existed for 50+ years. Who else are you going to charge with maintaining your standard that is 20+ years old and should perhaps have another 20 years or so to go?
Second, writing actual technical standards requires experts and a lot of time. Who is going to do it? The work is currently done by a dozen people or so who have quasi-guru status within their sponsoring companies. Who is going to put in the time like this in a volunteer organization?