I also had in the past legally blind co-workers that could barely use a browser, so they had their own problems with JavaScript overriding defaults.
By the look of it: if JavaScript proponents designed car doors, there would only be remote unlocking and no physical key.
It's just bad engineering lately beign promoted as 'the default way to build webpages'.
If I start my browser with JS enabled, it takes a few days and Firefox is at 100% CPU continuously, making my laptop battery last 2 instead of 5 hours, and if you start a packet sniffer, you see how all kinds of tabs are constantly reporting back to their mothership what I am doing.
That is why I keep JS disabled.
Also, most things that can be improved in websites (not to be confused with web apps) with JS would be better implemented as browser functionality.
My understanding is that javascript is a part of the web today, and everything around it makes it easier to run javascript applications in your browser, making websites more powerful. I personally love this and a lot of website I browse would be worse without javascript (google docs, calendar, etc.), so I have trouble understanding what is wrong with javascript running.
Also, since now most apps are complete javascript apps (and not only some DOM manipulation), it seems a lost cause to try to get website optionally "extend" their experience with javascript. That would mostly just imply to re-built most of the page for when javascript is disabled.