Not only is ISO full of DR and things that probably shouldn't have been standardized in first place (thankfully some of them were latter removed), there is plethora of compilers to chose from.
How were GC API, auto_ptr, modules, concepts and co-routines pretty well tested?
In those three compilers they surely weren't, so in which ones?
And folks using a full stack of MS tooling are probably using the EDG compiler as an implementation detail for IntelliSense support.
By the time all of that is supported for a language release we are on the next one, and I value that pipelene more than the changes currently being made.
Granted, the former can be quite a bit more severe - but that’s why we should do things like build on dedicated servers with restricted access to the internet etc.
This works as long as compatiblity-breaking changes are kept rare so that you can feasibly have someone doing security updates for each of the incompatible versions.
Most libraries have network access, but even if they didn't, supply chain attacks could be relavent (but probably less generic)