The advantages you listed are potential advantages but the reality is often different. Those features don't come for free, and given the number of SPA's out in the wild it's rare that functionality like offline mode or gracefully degrading when running into faulty network connections are actually built, let alone maintained.

Most of the time SPA's degrade very poorly and instead of breaking they often appear as if they're somewhat working but the site is actually in a broken state and will need a complete refresh to become usable again.