Because of the cargo culting, you see all sorts of Fortune 500 companies using this for fairly critical end-user tasks and failing at it. Air Canada did a redesign a while ago and I still can't book a flight on there. You look at the console and it's barfing all sorts of client-side errors and 500's. I would rather have a static, slow, reloading app that is reliable.

There are good uses for SPA's like ticket sites that have virtual queues and office applications. I just don't see the advantage SPA's give me for a lot of critical things I need to do in my life.