Considering that accessibility standards worldwide are mostly pushed forward by governments, even when there's action outside of it it's usually due to "government put laws stating specific requirements". While accessibility is usually afterthought unless directly whacked by a fine, and you can't just use "what's already available".

As for streamlining - this is streamlining, making it so that multiple entities within government that all need to build websites can use a common shared resource instead of duplicating the work (even "going shopping" for external solution takes valuable time).