I'm primarily a frontend dev, the vast majority of libraries and and browser APIs don't include offline documentation.

Well, I sad "quality" software. There is no quality whatsoever in the web frontend, unfortunately. Piles upon piles of an overengineered convoluted mess, but no "quality" code which can be even distantly compared to the glorious libraries of the past.

Be that as it may, I'm not convinced having no access to current documentation would help the situation!

If all the library developers were forced to work 80% of their time offline, things would definitely improve.