Comment by kizer

Here's the thing: so-called "JAM stack" apps are the cheapest to run, right? I realized this while I was thinking about how to create the cheapest site possible. Mainly, you want to minimize bandwidth. Well, SPAs are designed to do this. The site gets cached on the first hit, and runs usually JSON requests in the background after. So I think a big motivation for building SPAs is because they're cheap to host/run.