NEC 2020 brought more changes. The six simple sentences from 2014 have grown to a full page. Most of the addition is simply clarification of the requirements added in 2017. Since many states didn’t enforce the module level shutdown from 2017-2019, most people refer to 2020 as the release year that module level shutdown was added.
That does sound to me like some states decided it makes sense to not implement a part of the rules in 2017 because they considered the rules too burdensome/wanted to give companies more time.
One of the links in the OP says:
That does sound to me like some states decided it makes sense to not implement a part of the rules in 2017 because they considered the rules too burdensome/wanted to give companies more time.
https://www.renewableenergyworld.com/solar/evaluating-the-case-for-module-level-shutdown/ is an interesting article arguing that the rules that require the expensive module-level shutdown are essentially security theater.