It's like with C or C++. Most people that do write it shouldn't, because they are not good enough or the process is broken and they will shoot their leg. SPAs are the same way, because you have to implement all those normal website things again by yourself. There will be casualties.

Exactly, the problem is that you don’t get these baseline features for free. SPA, in my experience, is a lot of people poorly reimplementing the wheel.