Most sites are not going to have users viewing 100 pages within a single session / before the cache expires. If you can reuse a template that many times then SPAs make sense certainly. But for many sites (especially content focused ones) the math is harder than that.
Enterprise developer here (well mostly). I see this in most of our apps -- the same "template" is called hundreds of times in a session. An accountant auditing invoices is a perfect example.
Now for random public website? Depends on the content. In the blogs I've administered, I feel that the first page rendering speed is KEY to keeping traffic (ie static cache the html). However, new visitors, when given a quick way to get to new articles with a minimal amount of friction, tend to stay on the site longer.
Most sites are not going to have users viewing 100 pages within a single session / before the cache expires. If you can reuse a template that many times then SPAs make sense certainly. But for many sites (especially content focused ones) the math is harder than that.