All your critics is valid but you are beating the wrong horse. What you should have said — Dear Mr. Developer, please don’t build SPA until you learn it well enough. All those problems exist in the classical site just as well, and can be solved with SPA or not. What seems to be true, is that it might require more knowledge and experience for SPA.
But here is the bad news — you cannot avoid SPA at least in parts, unless you don’t want your user to wait and rely on their connection after Every. Single. Click. So now you have to manage both SPA and non-SPA sides of your app. Which is even harder than single SPA architecture done right. Welcome to the chaos :(