That is probably the wrong way to think about it. Its like saying "Well, we shouldnt be using motor cars because thats puts Horse carriages out of business". Or something to that effect.
We are moving towards a world where js is ubiquitous. Its everywhere..already. If web-crawlers dont support js completely ( looking at you google! ) then we should force them to (by creating more js based apps thats outside the crawlability of google ). If screen readers dont read js ( they should and thats why we have ARIA ), they will eventually. At the end of the day, as long as you are trying to adapt to them ( which is backward ) they will never move. Start moving swiftly and they will have to adapt to you.
In short, you imply the world's gone nuts and wants Turing-complete languages to be a strict requirement just to be able to display formatted text (with embedded multimedia objects).
Sorry, I'm just not comfortable giving anyone with a web server the permission to execute arbitrary code on my computer. I've had enough runaway 100% JS processes (hi, google code!) to make that obvious, not to mention the other benefits of blocking JS.
