Funny you should invoke turning off CSS and images -- a lot of people have actually worked pretty hard to make standards that
would work for cases where visitors had them disabled, or want low bandwidth options, or had their own custom style sheets, or weren't using a visual user agent (or even, for that matter, directing the user agent manually).
A failure of function availability from turning off images or CSS is a failure of developers, not a failure of the platform or user agent. You can find sites even in 2015 that either straight up work or degrade gracefully when being browsed by Lynx (a browser that I don't think has seen even a dot-release update since 1999) because they were put together by thoughtful professionals who understand the platform.
If you're trying to deliver an application that absolutely requires client side computation or specific browser APIs, you can have a pass for choosing the have your site not work without JS.
If your site really is just a series of documents (either static or dynamically computed), though, there really isn't much of an excuse.