Two words: Peer Review.
Standards are written with industry input all the time, this is completely uncontroversial. But when a binding standard is authored by just one supplying company, it almost always raises protests by other suppliers and by users who feel they may be stuck with a monopolist. The reason nobody except us hobbyists is worried about this standard is that it isn't used in binding documents.
Whenever standards, like those of the ISO, are used as a matter of course for contract specifications, controversial standards are peer reviewed in the relevant journals, or sent to neutral, respected engineering companies for the equivalent of a peer review.
For instance, suppose cafe water treatment systems were customarily bought via an RFP which contained binding specifications. And suppose that the SCAA were seen as a valid source for such specifications; which is something that every self respecting industry association attempts to become. Then the form and origin of this water treatment document would be suspect as soon as people found out that only the one company authoring it could fulfill the requirements.
But the SCAA does not act as a full scale industry association; it leaves that to the NCA. So it doesn't do specifications, it only does recommendations.
Back when the SCAA regarded itself as the organization that was the voice of all specialty coffee, from grower to drinker, its recommendations were carefully considered. Now, I'm no longer sure if it still regards itself as this voice. Sadly, without this self definition, it serves no purpose; if roasters and cafes just want a regular industry association, they are better off joining the NCA.
Just in case you're not sure what it means to be the voice of specialty coffee; here is an old document by Paul Katzeff, former SCAA president, the Cupper's Manifesto
. Read it, and think about today's SCAA.