Let me put it this way, both as a developer and user of SPAs, I have long since observed that SPAs, on average, tend to be much more resource intensive (it's not infrequent that my laptop fans start spinning), buggier, and harder to use. I don't think this is surprising, because "maintaining state" is great and all, but it also means that once that state goes sideways your app goes sideways, too.
Does this describe every SPA? No. Does that mean that every template app is better? No. But is the average SPA app worse than the average template app? In my experience it is (although I will admit I lack empirical data).
I don't think that popularity is a good yardstick. jQuery is clearly not the optimal way to develop web-apps – this post was never intended to argue as such, merely to argue that it's better than vanilla JS that I've seen advocated quite a lot recently – so people go to "alternative" solutions which lacks the problems jQuery has, but that doesn't mean these solutions don't create different problems on their own.
I don't know what the optimal way to develop webapps is, but I do know that the current generation of SPA frameworks isn't it. Probably some sort of hybrid approach, or a completely different one that hasn't been invented yet, is. In the meanwhile, a template-based approach is much easier to understand (less can go wrong), and is probably the best approach for many (though not all) websites.