Larger sites cater towards scriptless web for accessibility requirements.
Smaller sites don’t need SPA, so will most likely work to some degree.
The better (not necessarily bigger) blog systems will use scripting for fancy things, but will have fallbacks and will still work.

It’s the middle tier web-app (and sites that want to be a web app but have no reason to be) that will run SPA without any fallback. You know, the ones that want to send notifications and know your location and all that fun stuff.