Not at all: HTML compresses extremely well. CSS/favicon/etc are cached.
If you get rid of javascript frameworks used for SPA, the overhead of delivering a handful of HTML tables and forms instead of some JSON is negligible.
If you get rid of javascript frameworks used for SPA, the overhead of delivering a handful of HTML tables and forms instead of some JSON is negligible.
But that depends on the use case, doesn't it. Static sites may as well be huge, and now you need to send all of the surrounding html over, when only a small table or form would need updating. So I am not so sure about your point. The greater the complexity of the displayed page, the more sense it makes to use a SPA network-wise. (edit: mostly covered in sibling comments)
You have a point about compression though. I now wonder what the situation would look like if we had (had) native HTML imports, as that would greatly help with caching.
No, you don't. For something like the upvote button on HN you can do an ajax call with a line of javascript. In the context of the conversation this is very far from bloated SPAs.
HN is a good example: each thread page consists mostly of comments. Reusing the same DOM across different pages would do very little.
Gmail is another: the default UI is a heavy SPA. The "plain html" mode is not. And it's faster.