Each project has its own requirements, that lead to its own technology choices. Making everything a SPA is as idiotic as making nothing a SPA. It totally depends on your features, user base, server stack... If you have a complex, very dynamic, constantly updated app, with no support for old browsers, you should use an SPA. If your content is static, for old browsers, or users usually don't stay, your use of JS should be minimal.
Laziness when choosing your technologies is the issue here.