It's also things like HIPAA where you have to conform to certain electronic formatting standards that are non-public documents, where it's not strictly about safety, but creating an actual standard.
It's similar for electrical and structural codes: when I'm occupying a building (not just living or owning, but working or shopping too), I can trust that it meets certain standards as set by law. These things are codified by law to be minimum standards, not about making people liable to produce their own, as the past has been shown many times, there will always be people who will knowingly put money over the lives of people (e.g. via fake or otherwise unscrupulous insurance companies in this case). Now, I don't mean that insurance shouldn't or can't be a part of the "system", just that the "standard" shouldn't be whatever someone will insure.
Also, I'm not even advocating that copyright should be assigned to the government, just that access to the basic standards be free in perpetuity. This would prevent people from selling works composed primarily of the standard, but allow the basic standard to be freely accessible. I believe this would also cover annotated guides unless the annotations make up more of the work than the original standard does? The original organization still has the sole ability to sell authoritative supplementary and annotated materials. As long as the basic standard could reasonably be followed without said materials:
* a bad situation would be the standard saying to use the "appropriate wire gauge for the situation" but only give the appropriate guage in supplimentry material, and a
* good example would be the standard stating that "in a plenum, wire meeting «such and such» rating must be used", and as long as "«such and such» rating" is something that could reasonably be found on the wire itself then fine, even if the supplimentry materials make it easier to identify such cabling or find the most appropriate/cost effective type for a given situation, as long as any cable with the rating would be safe.
Professionals, especially if egged on by their insurance companies, would most likely purchase the authoritative materials. On the other hand general consumers doing work for themselves, could reference library copies or cheaper, non-authoritative references. Much as it is now for many things like major electrical and structural changes, inspections need to done by certified individuals, who require insurance, and who are probably only insurable if they have their own access to the standards and supplementary materials.
A similar situations that exist current is the "Manual on Uniform Traffic Control Devices for Streets and Highways". It is published by the as a free pdf by the Federal Highway Administration, but only a few partnered corporation are allowed to sell print copies. I cannot find a definitive answer as to why, but in the early 1970s the FHWA became the owner and began publishing it, but before that it was a joint consortium of private entites most of who are still involved in its development.
While discussing transportation, AASHTO's "A Policy on Geometric Design of Highways and Streets" (a.k.a. the "Green Book") contains guidance and standards. There are some documents published by the FHWA that come close to my good example above, but some fall into my bad example, where it says to consider this, but then gives not minimum design standards. So, in general that is a mixed bag, and could beuch better. However, I still think that both are illustrative that a system where the basics are available, but other commentary is paid.
There are other, transitionary, options for current standards even if, for instance, all new ones must be freely available.
For instance, it could be mandated that any standard that is currently proprietary, but required, must be held in some form at the county or local level in a manner accessible to the general public. The Green Book referenced earlier, could have to have a reference copy be available at a library in the county or a county office building open to the public. Similar to the electrical code, the general public doesn't need to have this constantly available to justify the money and storage space, but may have specific questions they want to look up, or verify for themselves.
Citizens have a right to know what the law is. That doesn't mean that the government can't work with technical organizations to ensure that while basic access is free, said organizations can still profit from the work they put in to create said standard.