Right, but I think those situations are far and few between. If you're a person who is regularly without internet access, there's probably better areas to work in than the web where you may need to deploy emergency fixes on short notice.

And regardless, it seems like offline web API documentation would make more sense as a one-time purchase? It's not like the web is rapidly evolving at all times, with major updates being released annually. It's a good chunk of years before enough browsers are updated to support new APIs, so if you grabbed the current docs you'd probably be able to work with that for a while.