Do you feel this way about dashboard apps? The OP is about a dashboard app, and I think they are one example where the benefits of a SPA framework really do make sense. Curious if these fit into the "almost all" criteria you use.
I think the main thing is that the downsides of SPA frameworks are significantly mitigated in a dashboard app.
Typically dashboards will be accessed on a desktop in an office setting with good internet, so initial load and asset size isn't a huge issue. Then you get benefits like client side routing which feels snappy, and live updating widgets is pretty simple. Of course it's a matter of opinion though.
I doubt that "client side routing" makes a site more snappy.
I think what you mean is that elements shared across pages (the header, the navigation bar etc) do not have to be sent again.
But those are very small anyhow. And you could bring the size down to zero by making them web components. Web components are cached along with the JS that defines them.
