[acdha]

It's fine to think of JavaScript as something that you depend on for major features but I still think you have to follow progressive enhancement. A small, but potentially growing, number of users have JavaScript disabled completely but a much larger number of people effectively have it disabled for a non-trivial period of time while things download or even, due to errors, until they reload the page.

If you don't degrade well under those circumstances you're at a competitive disadvantage to sites which do something like quickly return a core HTML page which can display immediately while the full app loads.